Peracetic acid (also known as peroxyacetic acid, or PAA), is an organic compound with the formula CH3CO3H. 
This organic peroxide is a colorless liquid with a characteristic acrid odor reminiscent of acetic acid. It can be highly corrosive.

Peracetic Acid (PAA) is a powerful disinfectant due to its high oxidizing potential, effectiveness against a broad range of microorganisms and its favorable environmental profile. 

PAA is a liquid organic acid and a very powerful oxidizer. It has a unique oxygen/oxygen bond arrangement that rapidly releases oxygen to destroy bacteria and oxidize unwanted odors (e.g., hydrogen sulfide) and compounds. When PAA is applied to a process it quickly degrades into non-harmful biproducts, acetic acid (a component found in table vinegar) and water. The residual acetic acid eats away at any inorganic scale and then breaks down into carbon dioxide and water.

Powerful oxidizer
Destroys bacteria
Non-harmful biproducts

Peracetic acid is a versatile oxidizing agent that dissolves easily in water and decomposes into non-toxic by-products. 
ATAMAN is one of the leading promoters of peracetic acid and has helped to develop a wide offering of high quality products, ranging in concentration from 5% to 40% peracetic acid in equilibrium solution.

The different concentrations are used in chemical synthesis, bleaching, sanitization, disinfection and sterilization across a variety of industries, including food and beverage, environmental remediation, industrial cleaning and sanitization, and oil and gas production.

Peracetic acid is a weaker acid than the parent acetic acid, with a pKa of 8.2

Peracetic acid (also known as peroxyacetic acid or PAA) is a colourless liquid with a boiling point of 25°C.

Holding the formula CH3CO3H, it is created by a reaction between hydrogen peroxide and acetic acid; the compound has a similar pungent-smelling odour to its slightly stronger cousin, acetic acid.

Peracetic acid is a popular biocidal disinfectant with uses across many industries.

Peracetic acid is biocidal — meaning it can destroy and control harmful bacteria, viruses, spores and fungi.

A very powerful oxidant and fast-acting antimicrobial, peracetic acid penetrates through cell membranes, irreversibly disrupting the enzyme system and destroying pathogenic microorganisms.

PAA’s antimicrobial properties make a popular, reliable biocidal disinfectant in agricultural, food and pharmaceutical settings, as well as in the home.

Amongst many other industrial applications, it also holds use in water treatment, able to prevent biofilm formation and pathogenic growth.

Efficacious even at low temperatures with no traces of chlorine, peracetic acid also has an environmental edge. After use, it simply breaks down into its ecologically-harmless components — an excellent alternative to traditional chemicals used for disinfectant and cleansing purposes.

Peracetic Acid (PAA) is a highly corrosive chemical used in hospital endoscopy, sterilization, poultry & meat processing, food processing, and many other industries. On this page we will cover the chemical properties, microbial activity, applications for use and hazards & risks.

Peracetic Acid, also known as peroxyacetic acid or PAA, is an organic chemical compound that is used in a mixture with acetic acid and hydrogen peroxide in water. It is a colorless liquid that has a strong vinegar like odor that can be smelt at very low levels. It is a strong oxidant and is highly reactive. However, it breaks down to acetic acid (vinegar) and water leaving no harmful residue, which makes it the chemical of choice when looking for a food-safe antimicrobial.

Peracetic Acid is produced by combining hydrogen peroxide, acetic acid and water. PAA functions as a disinfectant by oxidizing the outer cell membrane of microbes. The more concentrated the Peracetic acid solution, the more effective it is as an antimicrobial, but the greater the vapor concentration and so the greater the exposure risk to everyone around. This highly biocidial oxidizer shows good efficacy against a broad spectrum of pathogens.

Microbial Activity: PAA will inactivate  gram-positive and  gram-negative bacteria, fungi, and yeasts in <5  minutes at <100 ppm. In the presence of organic matter, 200-500 ppm  is required. For viruses, the dosage range is wide (12 -2250 ppm), with poliovirus inactivated in yeast extract in 15 minutes with 1500 to 2250 ppm. Bacterial spores in suspension are inactivated in 15 seconds to 30 minutes with 500 to 10,000 ppm (0.05 to 1%)

Preferred IUPAC name: Ethaneperoxoic acid

Other names
Peroxyacetic acid
Acetic peroxide
Acetyl hydroperoxide

CAS Number: 79-21-0 
EC / List no.: 201-186-8
CAS no.: 79-21-0
Mol. formula: C2H4O3

Acetic peroxide
Acetyl hydroperoxide
Acide peracetique
Acide peroxyacetique
Acido peroxiacetico
Desoxon 1
Hydroperoxide, acetyl
Kyselina peroxyoctova
Monoperacetic acid
Osbon AC
peracetic acid . . . %

Peracetic acid generated by perhydrolysis of N-acetylcaprolactam by hydrogen peroxide in alkaline conditions

Peracetic acid generated from 1,3-diacetyloxypropan-2-yl acetate and hydrogen peroxide
Peracetic acid generated from tetra-acetylethylenediamine (TAED) and sodium percarbonate
Peracetic acid generated from tetraacetylethylenediamine and hydrogen peroxide
Peroxoacetic acid
Peroxyacetic acid
Proxitane 4002

...% peroksiacto rūgštis (lt)
Acid peracetic (ro)
Acid peracetic sintetizat din tetraacetiletilenediamină (TAED) și percarbonat de sodiu (ro)
acid peracetic. . . % (ro)
acide peracétique à … % . . (fr)
Acide péracétique (fr)
Acide péracétique produit à partir de tétracétyléthylènediamine (TAED) et de percarbonate de sodium (fr)
Acido peracetico (it)
acido peracetico . . . % (it)
Acido peracetico ottenuto da tetracetiletilendiamina (TAED) e percarbonato di sodio (it)
Aċidu peraċetiku (mt)
Aċidu peraċetiku ġġenerat minn tetra-aċetiletilenedijamina (TAED) u perkarbonat tas-sodju (mt)
Kwas nadoctowy (pl)
kwas nadoctowy ...% (pl)
Kwas nadoctowy uzyskany z tetraacetyloetylenodiaminy (TAED) i nadwęglanu sodu (pl)
kyselina peroxyctová (sk)
kyselina peroxyoctová (cs)
kyselina peroxyoctová ... % (sk)
Kyselina peroxyoctová připravená z tetraacetyletylendiaminu (TAED) a peroxouhličitanu sodného (cs)
No tetra-acetiletilēndiamīna (TAED) un nātrija perkarbonāta iegūta peroksietiķskābe (lv)
Per-azijnzuur (nl)
Peracetic acid (no)
Peracetic acid generated from tetra-acetylethylenediamine (TAED) and sodium percarbonate (sk)
perazijnzuur . . . % (nl)
Perazijnzuur, verkregen uit tetra-acetylethyleendiamine (TAED) en natriumpercarbonaat (nl)
Perecetsav (hu)
perecetsav …% (hu)
pereddikesyre (da)
pereddikesyre . . . % (da)
Pereddikesyre genereret fra tetraacetylethylendiamin (TAED) og natriumpercarbonat (da)
pereddiksyre ... % (no)
Pereddiksyre generert fra tetraacetylendiamin (TAED) og natriumperkarbonat (no)
Peressigsäure (de)
Peressigsäure . . . % (de)
Peressigsäure, hergestellt aus Tetraacetylethylendiamin (TAED) und Natriumpercarbonat (de)
Peretikkahappo (fi)
peretikkahappo . . . % (fi)
Perocetna kislina (sl)
perocetna kislina, pridobljena iz tetraacetil etilendiamina (TAED) in natrijevega perkarbonata (sl)
perocetna kislina...% (sl)
Peroctena kiselina (hr)
peroctena kiselina . . . % (hr)
Peroctena kiselina dobivena iz tetraacetiletilendiamina (TAED) i natrijevog perkarbonata (hr)
Peroksiacto rūgštis (lt)
Peroksiacto rūgštis, gauta iš tetraacetiletilendiamino (TAED) ir natrio peroksokarbonato (lt)
Peroksietiķskābe (lv)
peroksyeddiksyre ... % (no)
peroxyoctová kyselina...% (cs)
Perättiksyra (sv)
perättiksyra . . . % (sv)
Perättiksyra som framställs från tetraacetyletylendiamin (TAED) och natriumperkarbonat (sv)
Peräädikhape (et)
Peräädikhape … % (et)
peräädikhape, mis saadakse tetraatsetüületüleendiamiinist (TAED) ja naatriumperkarbonaadist (et)
Tetra-asetyylietyleenidiamiinista (TAED) ja natriumperkarbonaatista tuotettu peretikkahappo (fi)
Tetraacetil-etilén-diaminból (TAED) és nátrium-perkarbonátból előállított perecetsav (hu)
Ácido peracético (es)
Ácido peracético (pt)
ácido peracético . . . % (es)
ácido peracético . . . % (pt)
Ácido peracético generado a partir de tetraacetiletilendiamina y percarbonato de sodio (es)
Ácido peracético produzido a partir de tetra-acetiletilenodiamina (TAED) e percarbonato de sódio (pt)
Υπεροξικό οξύ (el)
υπεροξικό οξύ . . . % (el)
Υπεροξικό οξύ που παράγεται από τετρα-ακετυλοαιθυλενοδιαμίνη (TAED) και υπερανθρακικό νάτριο (el)
Пероцетна киселина (bg)
Пероцетна киселина, генерирана от тетраацетилетилендиамин (TAED) и натрив перкарбонат (bg)
пероцетна киселина...% (bg)
…% paraetiķskābe (lv)

CAS names
Ethaneperoxoic acid

IUPAC names
Ethaneperoxoic acid
ethaneperoxoic acid

Peracetic acid
peracetic acid
Peracetic Acid
Peracetic acid
peracetic acid . . . %
peracetic acid ...%Peracetic acid anhydrous
Peracetic acid generated by perhydrolysis of N-acetylcaprolactam by hydrogen peroxide in alkaline conditions
Peracetic acid generated from 1,3-diacetyloxypropan-2-yl acetate and hydrogen peroxide
Peracetic acid generated from tetra-acetylethylenediamine (TAED) and sodium percarbonate
Peracetic acid generated from tetraacetylethylenediamine and hydrogen peroxide
Peroxyacetic Acid
peroxyacetic acid
Peroxyacetic acid - Aqueous stabilised solution
Peroxyethanoic Acid
Reaction mass of 64-19-7 and 7722-84-1
Reaction mass of hydrogen peroxide and water

Trade names

Peracetic acid is a colorless liquid with a strong, pungent acrid odor. Used as a bactericide and fungicide, especially in food processing; as a reagent in making caprolactam and glycerol; as an oxidant for preparing epoxy compounds; as a bleaching agent; a sterilizing agent; and as a polymerization catalyst for polyester resins

Peracetic acid is liquid that functions as a strong oxidizing agent. It has an acrid odor and is used as a disinfectant.

Peracetic acid is produced industrially by the autoxidation of acetaldehyde:

It forms upon treatment of acetic acid with hydrogen peroxide with a strong acid catalyst:

H2O2 + CH3CO2H ⇌ CH3CO3H + H2O
As an alternative, acetyl chloride and acetic anhydride can be used to generate a solution of the acid with lower water content.

Peracetic acid is generated in situ by some laundry detergents. This route involves the reaction of tetraacetylethylenediamine (TAED) in the presence of an alkaline hydrogen peroxide solution. The peracetic acid is a more effective bleaching agent than hydrogen peroxide itself.
PAA is also formed naturally in the environment through a series of photochemical reactions involving formaldehyde and photo-oxidant radicals.

Peracetic acid is always sold in solution as a mixture with acetic acid and hydrogen peroxide to maintain its stability. 
The concentration of the acid as the active ingredient can vary.

The United States Environmental Protection Agency first registered peracetic acid as an antimicrobial in 1985 for indoor use on hard surfaces. 
Use sites include agricultural premises, food establishments, medical facilities, and home bathrooms. 
Peracetic acid is also registered for use in dairy and cheese processing plants, on food processing equipment, and in pasteurizers in breweries, wineries, and beverage plants.
It is also applied for the disinfection of medical supplies, to prevent biofilm formation in pulp industries, and as a water purifier and disinfectant. 
Peracetic acid can be used as a cooling tower water disinfectant, where it prevents biofilm formation and effectively controls Legionella bacteria. 
A trade name for peracetic acid as an antimicrobial is Nu-Cidex.[8]

In the European Union, Peroxyacetic acid was reported by the EFSA after submission in 2013 by the US Department of Agriculture .

Decontamination kits for cleaning fentanyl analogues from surfaces often contain solid peracetyl borate, which mixes with water to produce peracetic acid.

Although less active than more acidic peracids (e.g., m-CPBA), peracetic acid in various forms is used for the epoxidation of various alkenes. 
Useful application are for unsaturated fats, synthetic and natural rubbers, and some natural products such as pinene. 
A variety of factors affect the amount of free acid or sulfuric acid (used to prepare the peracid in the first place).

Peracetic acid is a strong oxidizing agent and severe irritant to the skin, eyes, and respiratory system. 
The U.S. Environmental Protection Agency published the following Acute Exposure Guideline Levels (AEGL):

Chemical formula: CH3CO3H
Molar mass: 76.05 g/mol
Appearance: Colorless liquid
Density: 1.0375 g/mL
Melting point: 0 °C 
Boiling point: 105 °C 
Acidity (pKa): 8.2
Refractive index (nD): 1.3974 
Viscosity: 3.280 cP


Peroxyacetic acid

Ethaneperoxoic acid



Acetic peroxide

Peroxoacetic acid

Monoperacetic acid

Osbon AC

Acetyl hydroperoxide

Proxitane 4002

Desoxon 1

Hydroperoxide, acetyl

Ethaneperoxic acid

Caswell No. 644


Acide peracetique [French]


Acide peroxyacetique [French]

Acido peroxiacetico [Spanish]

Kyselina peroxyoctova [Czech]

HSDB 1106

EINECS 201-186-8


EPA Pesticide Chemical Code 063201

BRN 1098464



Peroxyacetic acid, >43% and with >6% hydrogen peroxide [Forbidden]

Acide peracetique

Acido peroxiacetico

Acide peroxyacetique


Kyselina peroxyoctova



peractic acid

per-acetic acid

Peroxacetic acid

Peroxyacetic acid, ca.35wt.% sol. in diluted acetic acid, stabilized

acetic acid oxide

Peroxy acetic acid


Acecide (TN)



Ethaneperoxoic acid, 9CI



$l^{1}-oxidanyl acetate

EC 201-186-8



4-02-00-00390 (Beilstein Handbook Reference)
























Peracetic acid solution, 8.7% in acetic acid



Peracetic acid solution, 36-40 wt. % in acetic acid

Peracetic acid solution 32 wt. % in dilute acetic acid

Peracetic acid solution, 32 wt. % in dilute acetic acid

Peroxyacetic acid, >43% and with >6% hydrogen peroxide

Peracetic acid solution, purum, ~39% in acetic acid (RT)

Peracetic acid solution, purum, ~40% in acetic acid: water

Disinfectants Peracetic acid
Peracetic acid

Peracetic acid (C2H4O3) is a mixture of acetic acid (CH3COOH) and hydrogen peroxide (H2O2) in a watery solution. 
It is a bright, colorless liquid that has a piercing odor and a low pH value (2,8). 
Peracetic acid is produced by a reaction between hydrogen peroxide and acetic acid:

|| ||
CH3-C-OH + H2O2 -> CH3C-O-OH + H2O

acetic acid + hydrogen peroxide -> peracetic acid

Peracetic acid can also be produced by oxidation of acethaldehyde. Peracetic acid is usually produced in concentrations of 5-15%.
When peracetic acid dissolves in water, it disintegrates to hydrogen peroxide and acetic acid, which will fall apart to water, oxygen and carbon dioxide. 
Peracetic acid degradation products are non-toxic and can easily dissolve in water.
Peracetic acid is a very powerful oxidant; the oxidation potential outranges that of chlorine and chlorine dioxide.

What are the applications of peracetic acid?

Peracetic acid is used mainly in the food industry, where it is applied as a cleanser and as a disinfectant. 
Since the early 1950’s, acetic acid was applied for bacteria and fungi removal from fruits and vegetables. 
It was also used for the disinfection of recicled rinsing water for foodstuffs.
Nowadays peracetic acid is applied for the disinfection of medical supplies and to prevent bio film formation in pulp industries. 
It can be applied during water purification as a disinfectant and for plumming disinfection.
Peracetic acid is suitable for cooling tower water disinfection; it affectively prevents bio film formation and controls Legionella bacteria.

How does peracetic acid disinfection work?

Peracetic acid as a disinfectant oxidizes the outer cell membranes of microorganisms. 
The oxidation mechanism consists of electron transfer. 
When a stronger oxidant is used, the electrons are transferred to the microorganism much faster, causing the microorganism to be deactivated rapidly.

Table 1: oxidation capacity of various disinfectants

EV (elektronic volts)


Peracetic acid

Chlorine dioxide

Sodium hypochlorite

Peracetic acid affectivity

Peracetic acid can be applied for the deactivation of a large variety of pathogenic microorganisms. 
It also deactivates viruses and spores. 
Peracetic acid activity is hardly influenced by organic compounds that are present in the water.
However, pH and temperature do influence peractetic acid activity. Peracetic acid is more effective when the pH value is 7 than at a pH range between 8 and 9. 
At a temperature of 15 °C and a pH value of 7, five times more peracetic acid is required to affectively deactivate pathogens than at a pH value of 7 and a temperature of 35 °C.

Discharge demands

When cooling tower water is tapped from a river or lake, and must be discharged into the same water body after it has been used, it must meet certain discharge demands. 
Aditionally, the water temperature may not be too high, because warm water has a low oxygen content, which promotes algal growth. This can cause fish mortality and a decrease in water biodiversity.

United States

Discharge demands for cooling tower water in the USA are mentioned in the Clean Water Act (CWA) and are established by the Environmental Protection Agency (EPA).

More information on water disinfection?:

Introduction water disinfection Necessity water treatment History of drinking water treatment

What is water disinfection? Necessity of drinking water disinfection History of water disinfection Waterborne diseases Factors that influence disinfection Conditions of water disinfection Regulation drinking water disinfection EU USA

Swimming pool treatment Swimming pool pollutions Swimming pool disinfection Swimming pool disinfection & health

Cooling tower water Cooling tower water pollutions Cooling tower water disinfection Cooling tower water legislation

Chemical disinfectants Chlorine Sodium hypochlorite Chloramines Chlorine dioxide Copper silver ionization Hydrogen peroxide Bromine Peroxone Peracetic acid

Disinfection byproducts Types of disinfection byproducts Research on health effects of disinfection byproducts

 Chlorinator system

Peracetic Acid Sterilization
Guideline for Disinfection and Sterilization in Healthcare Facilities (2008)

•    Overview
•    Mode of Action
•    Microbicidal Activity
•    Uses

Peracetic acid is a highly biocidal oxidizer that maintains its efficacy in the presence of organic soil. 
Peracetic acid removes surface contaminants (primarily protein) on endoscopic tubing.

An automated machine using peracetic acid to sterilize medical, surgical, and dental instruments chemically (e.g., endoscopes, arthroscopes) was introduced in 1988. 

This microprocessor-controlled, low-temperature sterilization method is commonly used in the United States.
The sterilant, 35% peracetic acid, and an anticorrosive agent are supplied in a single-dose container. 
The container is punctured at the time of use, immediately prior to closing the lid and initiating the cycle. 
The concentrated peracetic acid is diluted to 0.2% with filtered water (0.2 mm) at a temperature of approximately 50°C. 

The diluted peracetic acid is circulated within the chamber of the machine and pumped through the channels of the endoscope for 12 minutes, decontaminating exterior surfaces, lumens, and accessories. 
Interchangeable trays are available to permit the processing of up to three rigid endoscopes or one flexible endoscope. 
Connectors are available for most types of flexible endoscopes for the irrigation of all channels by directed flow. 

Rigid endoscopes are placed within a lidded container, and the sterilant fills the lumens either by immersion in the circulating sterilant or by use of channel connectors to direct flow into the lumen(s) (see below for the importance of channel connectors). 
The peracetic acid is discarded via the sewer and the instrument rinsed four times with filtered water.
Concern has been raised that filtered water may be inadequate to maintain sterility. 
Limited data have shown that low-level bacterial contamination may follow the use of filtered water in an AER but no data has been published on AERs using the peracetic acid system. 
Clean filtered air is passed through the chamber of the machine and endoscope channels to remove excess water.
 As with any sterilization process, the system can only sterilize surfaces that can be contacted by the sterilant. 
For example, bronchoscopy-related infections occurred when bronchoscopes were processed using the wrong connector. 

Investigation of these incidents revealed that bronchoscopes were inadequately reprocessed when inappropriate channel connectors were used and when there were inconsistencies between the reprocessing instructions provided by the manufacturer of the bronchoscope and the manufacturer of the automatic endoscope reprocessor. 
The importance of channel connectors to achieve sterilization was also shown for rigid lumen devices.
The manufacturers suggest the use of biological monitors (G. stearothermophilus spore strips) both at the time of installation and routinely to ensure effectiveness of the process. 
The manufacturer’s clip must be used to hold the strip in the designated spot in the machine as a broader clamp will not allow the sterilant to reach the spores trapped under it. 
One investigator reported a 3% failure rate when the appropriate clips were used to hold the spore strip within the machine.

The use of biological monitors designed to monitor either steam sterilization or ETO for a liquid chemical sterilizer has been questioned for several reasons including spore wash-off from the filter paper strips which may cause less valid monitoring. 
The processor is equipped with a conductivity probe that will automatically abort the cycle if the buffer system is not detected in a fresh container of the peracetic acid solution. 
A chemical monitoring strip that detects that the active ingredient is >1500 ppm is available for routine use as an additional process control.

Mode of Action
Only limited information is available regarding the mechanism of action of peracetic acid, but it is thought to function as other oxidizing agents, i.e., it denatures proteins, disrupts cell wall permeability, and oxidizes sulfhydral and sulfur bonds in proteins, enzymes, and other metabolites.

Microbicidal Activity
Peracetic acid will inactivate gram-positive and gram-negative bacteria, fungi, and yeasts in <5 minutes at <100 ppm. 

In the presence of organic matter, 200-500 ppm is required. 
For viruses, the dosage range is wide (12-2250 ppm), with poliovirus inactivated in yeast extract in 15 minutes with 1500 to 2250 ppm. 
Bacterial spores in suspension are inactivated in 15 seconds to 30 minutes with 500 to 10,000 ppm (0.05 to 1%).
Simulated-use trials have demonstrated microbicidal activity,and three clinical trials have demonstrated both microbial killing and no clinical failures leading to infection. 
Alfa and co-workers, who compared the peracetic acid system with ETO, demonstrated the high efficacy of the system. 
Only the peracetic acid system was able to completely kill 6-log10 of Mycobacterium chelonae, Enterococcus faecalis, and B. atrophaeus spores with both an organic and inorganic challenge.
Like other sterilization processes, the efficacy of the process can be diminished by soil challenges and test conditions.

This automated machine is used to chemically sterilize medical (e.g., GI endoscopes) and surgical (e.g., flexible endoscopes) instruments in the United States. 
Lumened endoscopes must be connected to an appropriate channel connector to ensure that the sterilant has direct contact with the contaminated lumen

Peracetic acid (CAS No. 79-21-0), also known as peroxyacetic acid or PAA, is an organic chemical compound used in numerous applications, including chemical disinfectant in healthcare, sanitizer in the food industry, and disinfectant during water treatment. Peracetic acid has also previously been used during the manufacture of chemical intermediates for pharmaceuticals. Produced by reacting acetic acid and hydrogen peroxide with an acid catalyst, peracetic acid is always sold in stabilized solutions containing acetic acid, hydrogen peroxide, and water. For the food and healthcare industries, peracetic acid is typically sold in concentrates of 1 to 5 percent and is diluted before use.

Many users know peracetic acid to be versatile and effective, and professionals with environmental responsibilities consider it to be environmentally friendly due to its decomposition products, which include acetic acid, oxygen, and water. However, industrial hygienists recognize that it is also highly corrosive and a strong oxidizer, and exposure to peracetic acid can severely irritate the eyes, skin, and respiratory system.

Also known as peroxyacetic acid (PAA), peracetic acid is best known for its ability to sanitize surfaces and objects. It "is characterized by a very rapid action against all microorganisms."

Peracetic acid is considered environmentally friendly due to its decomposition products, including acetic acid, oxygen, and water

Peracetic acid is an organic compound with the formula CH3CO3H. This organic peroxide is a colorless liquid that, with a pKa value of 8.2 and is weaker than its parent, acetic acid.

Some Peracetic Acid Uses
Peracetic acid has many applications in healthcare (e.g., cleaning contaminated surfaces and sanitizing surgical instruments). But its uses go beyond these.

Gnotobiotics is a form of laboratory research that focuses on pathogens. Totally germ-free animals are produced and live in sterile conditions for research studies. Peracetic acid is used to sterilize the isolation equipment.

Water Purification
Peracetic acid is also one of the substances used in the early phases of water treatment to destroy bacteria.

This chemical doesn't affect effluent toxicity, so it does not need to be removed like chlorine. Nor does its use result in toxic residuals, mutagenic, or carcinogenic compounds after disinfection.

The Pulp Industry
Paper mills and the pulp industry produce extremely large quantities of paper and pulp products each year.

However, paper happens to be the sixth-largest polluting industry and is known for producing toxic paper mill sludge due to the heavy use of chlorine for bleaching.

Peracetic acid has been shown as a potentially good alternative to chlorine in paper production and other bleaching processes.

The Food and Beverage Industries
Peracetic acid is used in food safety, especially in sanitizing fruits and vegetables for consumption and it has been used successfully in the production of both beer and wine.

Great Beer & Brewing, for example, points out that peracetic acid "breaks down readily into acetic acid (acetate), water, and atomic oxygen.
This form of oxygen poses no risk of oxidation to beers that come into contact with it. These breakdown products are environmentally friendly"

Peracetic Acid Dangers
Peracetic acid in low concentrations can irritate skin and eyes, as well as cause throat and breathing difficulties. 
However, in concentrated form, it can cause serious eye and skin damage.

When using manual immersion methods, peracetic acid requires adequate ventilation and personal protective measures like gloves and eye covering.

Peracetic acid is also flammable and explosive at temperatures above 40.5 degrees Celsius (104.9 Fahrenheit). 
There are also environmental risks; for example, peracetic acid is very toxic to aquatic organisms.

To ensure peracetic acid safety, we highly recommend peracetic acid monitors for the appropriate uses.

Peracetic acid is an organic acid generated by reacting acetic acid and hydrogen peroxide. Several commercial formulations are available. 
In solution, peracetic acid dissolves and forms back acetic acid and hydrogen peroxide. Peracetic acid is used at concentrations of 150–200 ppm on various food-contact surfaces. 
It is efficient in removing biofilms and works well at colder temperatures. 
Peracetic acid is believed to function in a similar fashion as other oxidizing agents by reacting with cellular proteins and enzymes. In a recent study, peracetic acid at 30 mg l−1 was shown to be more efficient than 250 mg l−1 of sodium hypochlorite at removing biofilm cells of S. aureus from stainless steel and polypropylene surfaces. 
Another study suggests that peracetic acid sanitizers may have some sporocidal activity against suspended bacterial spores in an aqueous solution on stainless steel surfaces. However, sporocidal activity was minimal against spores adhering to stainless 

Peracetic acid is presently utilized in several sterilization procedures. 
For the decontamination, disinfection, or sterilization of products, such as isolators and vapor-phase producers, peracetic acid was used. Peracetic acid, which is soluble in water, has a pungent odor and is a colorless liquid. In the market, it exists as a 35% or 40% solution. 
It is mostly found to be unstable, and easily decomposable (when in contact with oxygen, acetic acid, and other degradation products including hydrogen peroxide and water).

As supplied, peracetic acid is corrosive and has a very irritating smell, similar to vinegar; because of these properties, it is unpleasant to handle, and manual use is not recommended. It is suitable for CIP, as it is nonfoaming.

Peracetic acid is a highly reactive material. 
As an in-use solution, it is not very stable and will react with organic materials. 
Peracetic acid may attack plant materials, such as rubber gaskets, and at higher concentrations, corrosion may be a problem.

Peracetic acid has a wide antimicrobial spectrum, which includes bacterial spores and viruses. 
This activity is fast and is maintained at temperatures lower than ambient.

Peracetic, or peroxyacetic acid, is characterized by a very rapid action against all microorganisms. 
A special advantage of peracetic acid is its lack of harmful decomposition products (i.e., acetic acid, water, oxygen, hydrogen peroxide); it enhances removal of organic material155 and leaves no residue. 
It remains effective in the presence of organic matter and is sporicidal even at low temperatures. 
Peracetic acid can corrode copper, brass, bronze, plain steel, and galvanized iron, but these effects can be reduced by additives and pH modifications. 
The advantages, disadvantages, and characteristics of peracetic acid are listed in Table 301-2.

Peracetic acid will inactivate gram-positive and gram-negative bacteria, fungi, and yeasts in less than 5 minutes at less than 100 ppm. 
In the presence of organic matter, 200 to 500 ppm is required. For viruses the dosage range is wide (12 to 2250 ppm), with poliovirus inactivated in yeast extract in 15 minutes with 1500 to 2250 ppm. 
A processing system using peracetic acid at a temperature of 50° C to 56° C can be used for processing heat-sensitive semicritical and critical devices that are compatible with the peracetic acid and processing system and cannot be sterilized by other legally marketed traditional sterilization methods validated for that type of device (e.g., steam, hydrogen peroxide gas plasma, vaporized hydrogen peroxide). 
After processing, the devices should be used immediately or stored in a manner similar to that of a high-level disinfected endoscope.
The sterilant, 35% peracetic acid, is diluted to 0.2% with tap water that has been filtered and exposed to ultraviolet light. 
Simulated-use trials with the earlier version of this processing system have demonstrated excellent microbicidal activity, and three clinical trials have demonstrated both excellent microbial killing and no clinical failures leading to infection.
Three clusters of infection using the earlier version of the peracetic acid automated endoscope reprocessor were linked to inadequately processed bronchoscopes when inappropriate channel connectors were used with the system.
These clusters highlight the importance of training, proper model-specific endoscope connector systems, and quality control procedures to ensure compliance with endoscope manufacturer's recommendations and professional organization guidelines. 
An alternative high-level disinfectant available in the United Kingdom contains 0.35% peracetic acid. 
Although this product is rapidly effective against a broad range of microorganisms, it tarnishes the metal of endoscopes and is unstable, resulting in only a 24-hour use life

Peracetic acid is composed of an equilibrium of acetic acid, hydrogen peroxide and water. It is thought to act as an oxidising agent, denaturing proteins and disrupting cell walls.

The STERIS System 1E (STERIS Corporation, Mentor, OH) automated system uses peracetic acid diluted in sterile water to rapidly sterilise devices in 20–30 minutes. It can be corrosive to some metals, including copper, brass, bronze, steel and galvanised iron, so it must be combined with additives to reduce this effect. However, an advantage to using peracetic acid is that the liquid sterilant is able to flow through narrow lumens in endoscopes and sterilise them. As a sterilant, it is active against Gram-negative and positive bacteria, fungi and yeasts, but also against viruses and organic matter (Block 2001). Different doses of sterilant are needed to be effective against each of these organisms. This technique is to be used to sterilise instruments immediately prior to use; there is no storage of devices sterilised by this method.

Peroxyacetic, or peracetic, acid was the first germicide used to sterilize isolators and is still used because of its effectiveness, low cost, and compatibility with most plastics. It is effective at low concentrations and temperatures, and, in liquid form, in the presence of organic matter, although it does not penetrate parasite cysts and arthropod eggs (van der Gulden and van Erp, 1972). It is available from laboratory chemical suppliers as a liquid containing 40% peracetic acid. A major advantage of peracetic acid is that it is effective in vapor and liquid phases (Block, 2001; Trexler, 1984). The vapor generated when a 1–2% solution is sprayed at room temperature will inactivate the most resistant bacteria and mold spores within 15 min, and direct application of the liquid achieves the same action within 1 min (Trexler, 1984). Peracetic acid is sometimes used at a concentration of 4%, but there is no evidence from actual gnotobiotic applications that this is more effective than 1% (R. Orcutt, personal communication, March 2014). Optimal sporicidal activity in the vapor phase is achieved at 80% relative humidity. Peracetic acid solution should always be prepared immediately before use, because it loses about half of its strength within 24 h. Thirty minutes of contact time is sufficient. Peracetic acid is corrosive, and it is irritating to the eyes, skin, and respiratory tract. Personnel using peracetic acid should wear gloves, disposable clothing, and a full-face respirator with chemical filter cartridges. Peracetic acid is not considered a carcinogen by the Environmental Protection Agency, Occupational Safety and Health Administration, or the National Toxicology Program, and it is not genotoxic or mutagenic (Malchesky, 2001), although it can be a tumor promoter.

Combining peracetic acid with hydrogen peroxide results in synergistic antimicrobial activity (Block, 2001). Spor-Klenz™ (Steris Life Sciences), a ready-to-use sterilant solution containing 1% hydrogen peroxide and 0.08% peracetic acid, has broad sporicidal efficacy and completely inactivates Mycobacterium spp. after 20 min of contact time at 20°C (Rutala et al., 1991). It has become an accepted sterilant for gnotobiotics. A contact time of 1 h is recommended. Other products combining peracetic acid and hydrogen peroxide are available, as noted below.

Chlorine dioxide in liquid form is now the most commonly used sterilant in gnotobiotics. It is highly effective against all microorganisms, and, like peracetic acid, is effective in both gaseous and liquid phases (Jeng and Woodworth, 1990; Knapp and Battisti, 2001; Orcutt et al., 1981; Pell-Walpole and Waller, 1984). It is 1075 times more sporicidal in the gaseous state than ethylene oxide (Jeng and Woodworth, 1990). Liquid chlorine dioxide sterilants include Exspor™ (Ecolab Inc.) and Clidox-S™ (Pharmacal Research Laboratories). These are composed of two parts, a base solution of sodium chlorite and an acidic activator, which are combined and mixed with water immediately before application to form a solution of chlorous acid and chlorine dioxide. A contact time of at least 30 min is recommended. Such products can corrode stainless steel.

Steriplex™ SD (sBioMed) is a two-part product utilizing silver, peracetic acid, and ethanol (0.015%, 0.15%, and 10%, respectively, in the activated product). It is sold as a disinfectant, not a sterilant, for hospital and other applications. However, it is stated by the manufacturer to be sporicidal, bactericidal, fungicidal, and viricidal; to rapidly inactivate Clostridium difficile and Bacillus subtilis spores; to be nonirritating; and to have a shelf life of 60 days after activation (Robison, 2012; sBioMed, 2013a, b, c). Steriplex™ SD has begun to be adopted for gnotobiotic use (C. Bell, personal communication, January 2014). In our tests, Steriplex™ SD killed Geobacillus stearothermophilus 106 spore strips in 10 min and Bacillus atropheus 106 strips in 30 min.

Other liquid sterilant and ‘high-level’ disinfectant products include Actril™ (0.08% peracetic acid and 1.0% hydrogen peroxide; Mar Cor Purification), Cidexplus™ 28-Day Solution (3.4% glutaraldehyde; Johnson & Johnson), Minncare™ (4.5% peracetic acid and 22.0% hydrogen peroxide; Minntech BV), PeridoxRTU™ (4.0–4.8% hydrogen peroxide and 0.17–0.29% peracetic acid; Contec Inc.), Vimoba™ (chlorine dioxide; Quip Laboratories), Sanosil S010™ (5% hydrogen peroxide and 0.01% silver nitrate; Sanosil International), Sporgon™ (7.35% hydrogen peroxide and 0.23% PAA; Decon Laboratories), and Wavicide-01™ (2.65% glutaraldehyde; Medical Chemical Corporation). We are not aware of reports of evaluation of any of these products for use in gnotobiotics.

There is a large volume of literature on testing liquid sterilant and disinfectant procedures in health care and food processing; unfortunately, however, there is little information regarding comparative effectiveness or standardized testing as applied directly to gnotobiotics. Users should be aware that results of standardized testing methods can vary considerably. Organisms on surfaces are almost always more difficult to kill than those in suspension (Berube et al., 2001; Gibson et al., 1995; Sagripanti and Bonifacino, 1999, 2000; Springthorpe and Sattar, 2005; van Klingeren et al., 1998), and, in surface tests, different materials can yield different results (Thorn et al., 2013). Moreover, results of standardized tests do not necessarily indicate effectiveness in the environment in which sterilants and procedures will actually be used (Gibson et al., 1995; R. Orcutt, personal communication, March 2014). In our view, using standard laboratory tests to compare products well established to be effective sterilants when properly used is of far less value than determining that a sterilant’s applications – that is, the procedures in which it is used – are effective and reliable. Methods we use are described in relevant places in this chapter. A final recommendation is that although one chooses to verify liquid sterilization, it is important to determine that sterilization is real and not merely apparent due to growth inhibition. This can be done by use of dilution techniques, neutralizing media, or combinations of these. Dey–Engley neutralizing broth works well with chlorine dioxide and peracetic acid sterilants (Espigares et al., 2003; Sutton et al., 2002; Terleckyj and Axler, 1987). However, in our hands it did not neutralize Steriplex SD™.

Gnotobiotic facility personnel are advised to work with their institutional environmental health and safety personnel regarding the use of aerosolized sterilants. A work hazard assessment should be conducted to implement the use of the appropriate personal protective equipment (chemical respirator, gloves, goggles, face shield, etc.) and engineering controls such as exhaust air to scavenge chemical vapors away from personnel.

Peracetic acid - the new hero in hospitals

There have been many products tried and tested in the realm of hospital and healthcare in the quest to discover the most effective cleaner in an industry where hygiene is paramount.

Adam Duxbury, new product development chemist at specialist chemical company, Airedale Chemical, explains why there is a new hero product emerging that is ticking all the boxes for hospital buyers: peracetic acid (PAA).
The healthcare profession’s search to find the most effective cleaning products and methods is an ongoing pursuit with no clear ‘winner’ as yet, with several chemicals and solutions each with their own strengths and weaknesses. However, in recent years, peracetic acid (PAA) has emerged as the disinfectant of choice over other traditional methods of disinfection in healthcare environments.
Unlike bleach (sodium hypochlorite), it does not linger on surfaces. PAA components are completely biodegradable to its base elements of hydrogen peroxide and acetic acid.  In comparison to bleach, which requires rinsing after use, PAA does not need to be rinsed off surfaces. When used correctly, it can be used to sanitise surfaces, vessels, closed systems and equipment safely, ensuring surfaces remain sanitised until required.
This effective bactericide disinfectant, which also acts as a fungicide and sporicide is a broad spectrum product, generally considered a more powerful alternative to hydrogen peroxide. It breaks down the permeability of cell walls and oxidises enzymes, metabolites and proteins.
PAA rinses away completely, leaving no residue but is still able to kill many micro-organisms. It is often used as a destainer in laundry applications and is highly effective at low temperatures.
The low corrosion risk, which is in contrast to some disinfectants that can affect metal surfaces, means it can be safely used for the cleaning of many medical and dental instruments without having to worry about damage occurring.
It is now one of the most frequently used disinfectants for the sterilisation of medical devices such as endoscopy equipment as it has such potent disinfecting qualities but doesn’t leave behind any toxic deposits which could jeopardise patients’ health.
With efficiency being so high on the agendas of health authorities, the fact that PAA has such a long shelf life, coupled with its environmental credentials mean it is increasingly becoming the product which gives buyers value for money.
Only very low concentrations are required to achieve effective disinfection, particularly in comparison to bleach and hydrogen peroxide, where overdosing is a common mistake - making PAA not only a cost effective, efficient disinfecting choice but also a safer alternative for hospitals and end users.
Despite the many advantages of using PAA, there are still other products which have proven popular in the past and still hold a place in certain areas of healthcare hygiene.
Back to basics: bleach
Sodium hypochlorite is still used extensively in hospitals as a disinfection agent because the CRAs (chlorine release agents) it contains are highly effective for disinfection purposes although it is generally classed as an intermediate level disinfectant.
Its stain removal properties make it an ideal choice for cotton fabrics such as towels and bed linen which are prone to staining and tend to mark most easily, but can be recovered with bleach.
Unfortunately over-bleaching of this type of fabric item can compromise the fibre structure, diminishing the lifespan of sheets and other textiles. Neither are coloured fabrics suitable for sodium hypochlorite bleaching because of the effect it can have on the dye.
Bleach is still commonly used to disinfect blood spillages on hard surfaces and has been proven to remove the HIV and Hepatitis B virus when in the form of CRAs. These CRAs are so effective because they destroy the cellular activity of proteins and are highly active oxidising agents.
Sodium hypochlorite displays significant levels of sporicidal and virucidal eradication and has generally been accepted as the most effective defence against the digestive system infection clostridium difficile (C.Diff).
It is easy to see why it has played such a large part in the cleaning routines of hospitals and healthcare institutions. Its price point and low toxicity value mean it is still an essential part of the process today and is likely to be around for many years to come.
However it is not without disadvantages. It must be rinsed well from all surfaces due to its corrosive nature and while it is effective at killing microorganisms, the breakdown products from chlorine bleach can be harmful by-products and can be detrimental to aquatic animals and other creatures found in our waterways.
Bleach also contains products that are not compatible with certain types of materials and can have adverse reactions. Anyone handling sodium hypochlorite needs to wear appropriate PPE to avoid harm caused by exposure to the liquid or its vapours, which can be an additional cost and risk to health authorities and healthcare businesses.
The best of the rest
Hydrogen peroxide makes a great alternative to some other sterilisers which can be toxic which is why it is still used to disinfect some equipment such as endoscopy tools.
It is an effective bactericidal, virucidal, fungicidal and sporicidal making it a long-standing and popular option for high-level disinfection and sterilisation in the healthcare industry. It can also be used in a vapour form to clean rooms (HPV).
Ultra-violet light (UV) uses no chemicals so has been a popular alternative to traditional cleaning products in hospital cleaning and has been found to be effective against pathogens which are resistant to drugs and in particular to antibiotics.
It is used in sealed cabinets in which high energy UV light is emitted and disturbs the DNA of microorganisms, bacteria and other viruses by breaking bonds and inhibiting cellular functions.
UV is mutagenic to bacteria, viruses and other microorganisms. It kills or disables microorganisms which have little or no UV protection.
UV can be highly effective, however the capital investment of equipment associated with this type of disinfection is high and users would need specialist training to operate it safely. This is potentially prohibitive and means the safety of the user of UV disinfection equipment remains a continual concern. Therefore its use and practicality in hospital cleaning remains limited.
At the other end of the technology spectrum, the easy-to-use disinfectant trigger spray cleaning products are still used widely in the healthcare sector. Often found in the forms of chlorine releasing agents such as chlorides, isothiaolinones, alkonium and dimethylammonium, trigger sprays are at risk of leaving behind residue as they need to be in contact with surfaces for at least five minutes to be fully effective.
This residue could have serious implications in hospitals and healthcare establishments as it could affect food preparation and medication handling areas. So despite their simplicity it is easy for these products to be used incorrectly - which would be dangerous to human health in a healthcare environment.

What next for hospital cleaning?
There is still a place for many of these products in the healthcare sector and likely to be so for many years to come. 
Healthcare authorities are under increasing pressure to cut costs and stay safe, whilst still being mindful of the wider environment. 
Therefore we predict peracetic acid is destined to be the staple disinfectant for at least the near future in hospital cleaning and we are certainly expecting strong growth in the sector.

Peracetic acid is an exceptional broad-spectrum biocide and can be used in many industrial fields. 
If you are having problems with bacteria, fungi, spores and viruses, peracetic acid offers the right solution to maintain your hygiene standards.

Peracetic acid in low concentrations is effective against all types of microorganisms, even at low temperatures. 
As a result, peracetic acid stands for safe and environmentally friendly disinfection. 
After use, the peracetic acid breaks down into the ecologically harmless products oxygen, water and vinegar.

Peracetic acid (PAA) is produced by mixing acetic acid with hydrogen peroxide. In addition to peracetic acid, the resulting liquid concentrate also contains acetic acid, hydrogen peroxide, water and stabilizers.

In what fields is peracetic acid used?
Peracetic acid is a reliable disinfectant and is used in a wide range of fields:

Commercial launderettes
Food and drinks industry
Agriculture/veterinary hygiene
Pulp and paper industry
Water and wastewater treatment
Hospital hygiene

A powerful and sustainable sanitizer: Peracetic Acid
Industries across the globe are dealing with two major trends developing in parallel: rising standards for disinfection accompanied by growing environmental scrutiny. Solvay’s peracetic acid (PAA), a colorless, liquid organic formulation, responds to both these trends. As the leading global supplier of high-quality PAA, Solvay draws upon years of experience to formulate this highly effective biocide for use in a growing number of applications:

Disinfecting and sterilizing equipment and packaging to guarantee food quality and safety
Protecting animal health and welfare by disinfecting houses and equipment
Providing peracetic acid for the final treatment step in wastewater purification
Cleaning and disinfecting industrial laundries used by hospitals and hotels
Washing fruits, vegetables and meats to protect against harmful pathogens and food spoilage without impacting food quality
Oxygenating soil through irrigation systems in the agricultural industry  
Protecting against biofouling in paper production

While peracetic acid has a burgeoning, results-based reputation for various applications in sanitation, disinfection and sterilization; it also provides an eco-friendly alternative to harsher products on the market. Similar to hydrogen peroxide, PAA decomposes into everyday molecules found all around us: water, oxygen and acetic acid ౼ a readily biodegradable molecule. 

Key Markets
Aseptic Packaging 
Cleaning in Place
Food & Beverages 
Food Processing
Pulp & Paper 
Wastewater Treatment 

Peracetic acid, also known as peroxyacetic acid or PAA, is used in numerous applications, including as a chemical disinfectant in healthcare, sanitizer in the food industry, and purifier during water treatment. It’s an often preferred cleaning agent because it leaves no toxic residue and it is no-rinse.[1]

Given PAA’s increasing popularity and use throughout multiple industries, more attention is now being focused on health hazards and associated risks when PAA is used in the workplace.[2] Moreover, peracetic acid’s ability to become airborne, the varying concentrations that may be used, and the relatively low occupational exposure limits (OELs) mean that if you are going to use PAA, there is an increased need to review company risk assessment procedures and personal protective equipment (PPE) choices for various applications of this substance.

Here, we will take a deeper dive into what peracetic acid is, the hazards employees may face if exposed to it, and controls employers can consider taking to help protect employees

PAA is an organic compound produced by reacting acetic acid, a component of vinegar, and hydrogen peroxide. This creates an equilibrium mixture of acetic acid, hydrogen peroxide, and peracetic acid. The vapor above a peracetic acid solution contains all three of these compounds.

Peracetic acid is a strong oxidizer and a highly reactive, unstable, volatile peroxide-based molecule for which there is currently no NIOSH recommended exposure limit (REL) or OSHA permissible exposure limit (PEL). However, there are other established exposure limit values for peracetic acid, which include:

American Conference of Governmental Industrial Hygienists (ACGIH) has published a threshold limit value–short-term exposure limit (TLV-STEL) of 0.4 ppm (1.24 mg/m3)
EPA’s National Advisory Committee for the Development of Acute Exposure Guideline Levels (AEGLs) for Hazardous Substances has published acute exposure guideline levels (AEGLs)
NIOSH has proposed 0.64pm (1.7mg/m3) as an immediately dangerous to life and health (IDLH) concentration value, which is currently under review[3]
The state of California HEAC is considering a PEL of 0.2ppm per 8hr TWA[4]
For more information, please see the technical data bulletin entitled: Worker Personal Protective Equipment (PPE) Tips for Peracetic Acid Use in Pharmaceutical Manufacturing.

In terms of potential health effects, PAA may be corrosive to eyes and skin with direct contact and has some volatility, so worker exposure can occur to airborne aerosol and vapor. EPA’s National Research Council (US) Committee on Acute Exposure Guideline Levels reports “peracetic acid can be corrosive/irritating to the eyes, mucous membranes of the respiratory tract, and skin. It may cause lacrimation (tears), extreme discomfort, and irritation to the upper respiratory tract in humans after exposure to concentrations as low as 15.6 mg/m3 (5 ppm) peracetic acid for only 3 min. ”[5] So, how can employers help protect workers from the hazards associated with PAA?

Hierarchy of Controls

The hazard classification of PAA under the Globally Harmonized System (GHS) will vary depending on the chemical concentration and product formulation of the PAA product being used, but typical disinfectant products may be classified as flammable, oxidizer, toxic, corrosive and hazardous to the environment.

Employers should continue referring to safety data sheets (SDS) for guidance. James M. Boiano, MS, CIH, a senior industrial hygienist and assistant coordinator of the NIOSH Healthcare and Social Assistance Sector Program says, “The OSHA Hazard Communication standard requires that these sheets be available in the workplace to ensure that workers have access to information on the hazards each chemical pose and the proper techniques for handling, storage and transportation. Study this information carefully, then proceed with caution.”[6]

“This would include implementing the hierarchy of controls in the following, decreasing order of efficacy: substitution, engineering controls, following administrative controls, work practice controls, and personal protective equipment (PPE),” Boiano says. “Should workers experience symptoms related to exposure to PAA, they should notify their employer’s health and safety department, occupational health unit, or their doctor so that the work environment is evaluated, and corrective actions can be taken.”[7]

PAA Use in Pharmaceutical and Medical Applications

Peracetic acid is commonly used as a broad-spectrum biocide in medical and industrial applications. It is a powerful oxidizing agent that kills microorganisms by penetrating the cell wall. It is even effective against anthrax spores.[8]

PAA-containing products can have many applications where pharmaceuticals are manufactured, processed, or administered. These activities often are accompanied by cleaning, sanitizing, disinfecting, sterilizing, or neutralizing and PAA-containing products may be chosen by facilities for all these tasks. Increased use of PAA may also occur due to increased public scrutiny and regulatory pressure around contaminated products and worker health.

The nature of these cleaning and disinfecting tasks often means repeatedly using higher PAA concentrations spread over large surface areas, which may result in significant worker exposures. Keep in mind that these EPA-regulated products must be used according to label directions, which can limit potential opportunities for reducing exposure by changing the way a product is used (such as not spraying when the product label indicates to apply using a sprayer or not maintaining a wet surface for the prescribed contact time).

Air monitoring for PAA can be challenging because it is highly reactive, it can quickly degrade, it is commonly found with other components, and the lack of a NIOSH or OSHA validated sampling method. Improvements for monitoring are in demand because of the increased marketplace use of these products and evolving exposure concerns. Qualitative assessments can be performed that are more academic and based on modeling, though that has proven to be challenging. Also, quantitative exposure assessments should be conducted where required.

Air monitoring methods can be divided into two main types: direct-reading where a device can provide results right away, often in real-time as the work tasks are being conducted; and methods that require laboratory analysis, so results are not available until later and typically only represent an average concentration over the time period sampled (Time-Weighted Average or TWA). To learn more about air monitoring methods that can help inform safety decisions, please see the technical data bulletin entitled: Worker Personal Protective Equipment (PPE) Tips for Peracetic Acid Use in Pharmaceutical Manufacturing.

Exposure controls that reduce chances of inhalation should be considered where an employer’s risk assessment indicates that the respiratory hazard may result in unacceptable exposures.

Peracetic Acid Use in the Food and Beverage Processing Industry

PAA-containing products can have many applications where poultry, meat, vegetables, and beverages are processed. These activities often are associated with cleaning, sanitizing, or sterilizing and PAA-containing products may be chosen for all these tasks where appropriate. Increased use of PAA may also be expected due to increased public scrutiny from food recalls and increasing Hazard Analysis Critical Control Point (HACCP) FDA regulatory pressure around contaminated food products.

According to the USDA Food Safety Inspection Service fact sheet, if appropriate controls are not in place, employees may potentially be overexposed to PAA from the following operations in food, meat, or poultry processing facilities:[9]

Inadequate ventilation: poor local exhaust ventilation on spray cabinets, off-gassing from chillers, inadequate ventilation on the kill floor
Splashes and overspray from spray cabinet openings and high nozzle pressure, chemical mixing in floor drains, hand application with spray tanks, and discharge of waste solution from cabinets and tanks directly onto the floor
Failure to properly control solution pH may also contribute
Keep in mind that these EPA and USDA regulated products must be used according to label directions or prescribed concentrations for food quality, which can limit potential opportunities for reducing exposure by changing the way a product is used (such as not spraying when the product label indicates to apply using a sprayer, not maintaining a wet surface for the prescribed contact time or reducing concentrations).[10]

The USDA Food Safety Inspection Service fact sheet also suggests providing proper ventilation, containment, and process controls to reduce employee’s exposure to PAA vapor, mists, and droplets. These controls could include local exhaust ventilation, shielding of spray areas, and dedicated drainage.

How Do You Choose the Right PPE to Help Protect Against PAA?

OSHA, the EPA, and FDA provide guidance about the use of products containing PAA. Employers should thoroughly consult applicable guidance when determining what PPE may be needed based on how workers are exposed to PAA in the workplace. For an overview related to pharmaceutical manufacturing, please review our technical data bulletin entitled: Worker Personal Protective Equipment (PPE) Tips for Peracetic Acid Use in Pharmaceutical Manufacturing.

Respirator manufacturers may also have publications that can help employers with their respirator selection for PAA. Information on the type of respirator recommended (including cartridge and filter if applicable), along with cartridge service life data, should be requested from the supplier to help the employer satisfy the requirements of the OSHA Respiratory Protection Standard (29 CFR 1910.134). See our technical bulletin #185: Respiratory Protection for Hydrogen Peroxide, Peracetic Acid, and Acetic Acid, for more information on respirator products for PAA. Employers may want to consider respiratory protection that includes suitable eye protection such as a full facepiece respirator or a powered air-purifying respirator (PAPR) with appropriate headgear due to the eye irritation potential of PAA-containing products.

Employers should also consider other appropriate PPE for eye and skin protection due to the potentially irritating or corrosive nature of PAA. Tasks that may result in eye or skin contact with liquid require eye and face protection, gloves, and body coverings such as coveralls. Vapor or aerosol presence may require goggles or respiratory protection that includes suitable eye protection. Manufacturer-provided selection guides may be helpful in choosing appropriate eye and skin protection. Keep in mind the nature of the task, including chemical concentration and extent of potential eye and skin contact, when selecting PPE.

If you have questions or need more information about respiratory protection selection or other PPE when using PAA, please contact our technical specialists for assistance.

Peracetic Acid safety is a major concern for anyone potentially exposed because PAA is corrosive to the eyes, the skin and the respiratory tract.  Exposure to peracetic acid can occur from inhalation and / or direct contact with the liquid or aerosol. According to NIOSH, symptoms of acute exposure to peracetic acid vapor include cough, labored breathing, and shortness of breath; skin redness, pain, and blisters; severe deep burns to the eyes.  Concentrations of 15% or higher, also give rise to fire and explosion hazards and reactivity issues. It is important to ensure that training for use and safety precautions for peracetic acid are in place.

Another major concern is that peracetic acid has a vinegar type odor, even at low levels, so the challenge becomes knowing if your level of exposure is safe... whether you smell it or not.  If you are working around PAA and over time you do not smell it, it may be due to olfactory fatigue. Olfactory fatigue is also known as nose blindness or odor fatigue. In summary, your sense of smell is an unreliable means of protecting yourself from over-exposure to PAA. So, while making sure the items you're disinfecting are safe for others, be sure to keep track of peracetic acid exposure levels for your own safety and others in the work environment. 

What Is Peracetic Acid (PAA)?
Peroxyacetic acid, Peracetic acid, or PAA as it is commonly known, is a strong oxidising agent with excellent disinfectant properties. PAA is an organic acid with an acrid odour, represented by the formula CH3CO3H.

What Is Peracetic Acid (PAA) Used For?
Peracetic acid is a common disinfection widely used in the food and beverage market and in the healthcare industry. A more powerful oxidizing agent than its chlorine counterparts, PAA has become increasingly popular since it was first registered as an antimicrobial substance in 1985.

As with all disinfectants, monitoring of residuals and dosing is important to ensure that levels are not too high or low. However, unlike other common sanitizers, it is effective at weakly acidic pH levels and its efficacy is not greatly impacted by temperature.

Peracetic acid (PAA) is described as an efficient “broad spectrum biocidal agent”. This means that it will effectively kill the majority of bacteria, including E. coli, Listeria and Salmonella which all cause food poisoning/gastrointestinal illnesses, and pseudomonas which can cause chest and blood infections.

Just like chlorine, PAA is an oxidizing agent, and works as a disinfectant by damaging the cell walls of microorganisms that are present in the water. Once the cell wall is damaged, the bacteria will die, and so no longer pose a threat to human/animal health.

PAA is widely used as a disinfectant across the food and beverage industry, including for dairy, meat, poultry, brewing and bottling applications. To find out about the role of PAA in the poultry industry read our support article What Role Does Disinfection Play in Poultry Processing in the US. 

A relatively expensive sanitiser, PAA is popular due to reduced levels of disinfection by-products (DBP) because it breaks down into food-safe and environmentally friendly residues. PAA is effective in reducing the microbial load of wash water and reducing cross-contamination in food and beverage products.

The US Food and Drug Administration (FDA) limits concentrations in produce wash water, and the Environmental Protection Agency (EPA) regulates PAA as a general use pesticide.

A study by CEBAS has identified Palintest sensor technology as the best method for testing PAA in produce wash water. The study compared how 5 different test method measured PAA in four types of wash water. Our chronoamperometric sensor was found to be the best test method offering precise, real-time monitoring of wash water. Find out more about the study and why Kemio has been identified as the best method here.

PAA is a disinfectant used to kill harmful bacteria from drinking water streams. It produces fewer harmful DBPs than its chlorine counterpart.

Dosing control is critical in drinking water to ensure that the water has been effectively ‘cleaned’ but is not overdosed, posing potential danger, as well as affecting the taste of the final product.

PAA is used in a similar way to chlorine to help with debulking sludge in wastewater, as well as an effective disinfectant and odour control agent. For wastewater applications, dosing control is vital to protect aquatic life and the environment.

PAA is used in some laundry detergents as a bleaching agent. As it is a more effective bleaching agent than hydrogen peroxide, the peroxide is converted to PAA using a catalyst to enhance the cleaning power of the detergent during the wash.

Peracetic acid is rapidly tidal at low concentrations against a broad spectrum of microorganisms, including gram-positive and gram-negative bacteria, yeasts, molds, and algae under a wide variety of conditions. It is also effective against anaerobic and spore forming bacteria. Peracetic acid is affective at killing biofilm microorganisms at low concentrations and short contact times. Unlike a number of other biocides, the biocidal activity of peracetic acid is not affected by pH or water hardness and biocidal activity is retained even in the presence of organic matter. For these reasons, peracetic acid is well suited as a biocide in industrial cooling water and papermaking systems. Peracetic acid is compatible with additives commonly used in these systems. Although peracetic acid is a potent biocide, it is unique in that it does not produce toxic byproducts and its decomposition products, acetic acid, water and oxygen, are innocuous and environmentally acceptable.

Demand for microbial growth control is increasing throughout the industrial water treatment sector. Microbial growth in cooling water, process water, and water purification systems causes reduced heat transfer efficiency, reduced flow, blockages, corrosion, and loss of yield. The conventional method of controlling microbial growth is through the use of organic biocides. While organic biocides do inhibit microbial growth, economic and environmental concerns require improved methods. For these reasons, there is increasing interest in the use of peroxygen compounds as biocides in industrial water treatment applications.

Hydrogen peroxide has received attention over the years as a potential biocide for industrial water treatment applications. One advantage of using hydrogen peroxide is that no harmful decomposition products preformed. Factors which have limited these of hydrogen peroxide in industrial water treatment applications include poor activity at low temperatures and concentrations and decomposition by catalase and peroxidase.

It would be desirable to have a biocide with the advantages of hydrogen peroxide but with greater biocidal active and freedom from inactivation by catalase and peroxidase. The peroxide of acetic acid, peroacetic acid, or peracetic acid is such a biocide. Peracetic acid formulations are equilibrium mixtures containing peracetic acid, hydrogen peroxide, acetic acid, water and stabilizer. The equilibrium mixture is shown in equation 1:

Peracetic acid is a more potent biocide than hydrogen peroxide, being rapidly tidal at low concentrations against abroad spectrum of microorganisms.1 The biocidal activity of peracetic acid is due to the oxidation of sulfhydryl groups, disulfide bonds, and double bonds in proteins, lipids and other cellular constituents which disrupts the chemiosmotic and transport functions of the cell membrane.2 Although peracetic acid is a potent biocide, it is unique in that it does not produce toxic byproducts and its decomposition products, acetic acid, water and oxygen, are innocuous and environmental acceptable Decomposition routes for peracetic acid are given in equations 2-4 :

Peracetic acid has previously only been used in the U.S. in the food industry at high concentrations (100-500 ppm peracetic acid).


Biodegradable, low residue peracetic acid disinfectant. An effective and versatile oxidising disinfectant which can be used for terminal disinfection (buildings, water systems, pathways etc), fogging and water sanitisation.

Chemical Names:
Peracetic acid; Ethaneperoxoic acid (IUPAC name); Acetic peroxide; Monoperacetic acid; Peroxoacetic acid; Acetyl hydroperoxide

Peracetic acid (PAA) is currently allowed under the National Organic Program (NOP) regulations for use in organic crop production, organic livestock production, and in organic food handling. 
This report addresses the use of peracetic acid in organic processing and handling, including post-harvest handling of organically produced plant and animal foods. 
Peracetic acid is currently allowed for use in organic handling in wash water and rinse water, including during post-harvest handling, to disinfect organically produced agricultural products according to FDA limitations, and to sanitize food contact surfaces, including dairy-processing equipment and food-processing equipment and utensils

Peracetic acid
Also known as peroxyacetic acid (PAA). The colourless organic acid with a characteristic acrid odour belongs to the group of peroxy acids and arises upon treatment of acetic acid with hydrogen peroxide. The organic compound dissolves in water and is characterised by a strong oxidising effect. Due to the latter, it is used as bleaching agent, but also as disinfectant, e.g. for surface and instrument disinfection. Its spectrum of activity comprises Gram-negative bacteria, fungi and viruses. PAA’s fixating properties in case of organic soils can have drawbacks when used as disinfectant.

Medical Definition of peracetic acid
: a corrosive toxic strongly oxidizing unstable pungent liquid acid C2H4O3 used chiefly in a solution in acetic acid or an inert solvent in bleaching, in organic synthesis, and as a fungicide and disinfectant

Composition of the Substance: 32 Chemically, the term “peracetic acid” describes two substances. 
“Pure” peracetic acid, described in the Merck 33 Index (Budavari 1996), has the chemical formula C2H4O3 (alternatively written CH3CO3H). 
Anhydrous peracetic  acid explodes violently upon heating. 
In contrast, solutions of peracetic acid used as sanitizers are created by combining aqueous mixtures of two substances: acetic acid (the acid in vinegar) and hydrogen peroxide. 
At cool temperatures, acetic acid and hydrogen peroxide react over a few days to form an equilibrium solution  containing peracetic acid, acetic acid and hydrogen peroxide. 
This equilibrium solution is the substance sold  commercially as the sanitizer “peracetic acid.” 
Adding a mineral acid catalyst accelerates the reaction.  
Peracetic acid is an unstable oxidizing agent, which is why it is such an effective sanitizer. 
Most commercial peracetic acid solutions contain a synthetic stabilizer and chelating agent such as HEDP (1-hydroxyethylidene 1, 1-diphosphonic acid) or dipicolinic acid (2,6-dicarboxypyridine) to slow the rate of oxidation or decomposition.

Properties of the Substance:  Pure anhydrous peracetic acid is a colorless liquid with a strong, pungent acrid odor.
 It is an organic  substance which is completely miscible with water (water solubility of 1000 g/L at 20 °C) and is also soluble in ether, sulfuric acid and ethanol. It is a strong oxidizing agent – stronger than chlorine or  chlorine dioxide (Carrasco and Urrestarazu 2010). 
It is highly unstable and decomposes to its original  constituents under various conditions of temperature, concentration and pH. Peracetic acid decomposes  violently at 230ºF (110ºC). 
Peracetic acid diluted with 60% acetic acid, when heated to decomposition,  emits acrid smoke and irritating fumes. 
 Pure peracetic acid is not commercially available because it is explosive. For this reason it is not technically possible to determine the melting point, boiling point and vapor pressure of pure peracetic acid experimentally. Estimates based on modeling have been reported as -42 °C for melting point, about  105 °C for boiling point and 32 hPa at 25 °C for vapor pressure. 
The properties of commercial peracetic acid solutions vary based on concentrations (ratios) of their components (peracetic acid, hydrogen  peroxide, acetic acid and water) for different grades. The physical and chemical properties of commercial  equilibrium grades of 5% - 35% PAA are generally consistent in composition

Specific Uses of the Substance:  The primary use of peracetic acid is as a bactericide and fungicide, especially in food processing. 
The  current NOP regulations permit the use of peracetic acid as a disinfectant in wash water and rinse water  for raw and processed fruits and vegetables and meat and eggs (direct food contact) according to FDA  limitations, and as a sanitizer on food contact surfaces. 
Peracetic acid can be utilized over a wide temperature spectrum (0 to 40ºC), in clean-in-place (CIP)  processes, and in carbon dioxide-saturated environments. It can also be used with hard water. In addition, protein residues do not affect its efficiency. No microbial resistance to peracetic acid has been  reported. 
It is efficient over a wide spectrum of pH values, from 3.0 to 7.5 (Kunigk and Almeida 2001)

Peracetic acid was first registered in the U.S. as a pesticide for use as a disinfectant, sanitizer and sterilant in 1985

Peracetic acid preparations usually contain a synthetic stabilizer such as HEDP (1-hydroxyethylidene-1,1-  diphosphonic acid) or dipicolinic acid (2,6-dicarboxy-pyridine) to slow the rate of oxidation or  decomposition of peracetic acid (Kurschner and Diken 1997). 
These stabilizers are chelating agents that  bind with metal ions and reduce their activity in solution. 
Synthetic stabilizers can be avoided if the  peracetic acid solution is produced on site as described for PAA solution #4 in Evaluation Question 2. 
HEDP (CAS No. 2809-21-4) historically was classified by EPA as a List 4 inert. 
It is also exempt from the requirement of a tolerance when used as a stabilizer/chelator in antimicrobial pesticide formulations at not more than 1 percent (40 CFR 180.910).

HEDP and dipicolinic acid (DPA) are added to peracetic acid solutions to chelate metals, especially iron,  copper and manganese, because decomposition of peracetic acid and, thus, loss of sanitizing power is  accelerated by these impurities. Internationally accepted toxic heavy metal limits, reported as lead, are  not more than 0.5 ppm for glacial acetic acid, 4 ppm for hydrogen peroxide, 5 ppm for HEDP, and 2 ppm  for octanoic acid. The maximum limit for arsenic in HEDP is 5 ppm (Azanza 2004). The Food Chemical  Codex (FCC) heavy metal maxima are 0.5 ppm for lead in glacial acetic acid, 4 ppm for lead in hydrogen  peroxide, and 3 ppm for arsenic and 5 ppm for lead in concentrated sulfuric acid. There are no FCC heavy  metal limits set for octanoic acid, HEDP, or DPA (U. S. Pharmacopeia 2010).

Peracetic acid is highly soluble in water (1000 g/L at 20ºC) and is also a highly reactive oxidizer (OECD  2008). Based on its vapor pressure, PAA could be expected to exist primarily in the gas phase in the  atmosphere (California Air Resources Board 1997b). However, due to its solubility, it readily dissolves in Technical Evaluation Report Peracetic Acid Handling/Processing March 3, 2016 Page 15 of 20  clouds and is removed from the atmosphere through rain-out (U.S. National Library of Medicine 2011;  California Air Resources Board 1997a). PAA occurs, therefore, almost exclusively (99.95%) as a liquid in  the environment. 
 In air the half-life of peracetic acid is 22 minutes. The abiotic degradation of peracetic acid increases with  temperature and higher pH. At a temperature of 25 °C and at pH of 4, 7 and 9, the degradation half-life  values were 48 hours, 48 hours and less than 3.6 hours, respectively (OECD 2008). 
 Peracetic acid exerts its oxidizing effect on contact with reducing materials (Massachusetts Department of  Environmental Protection October 2010), breaking down to water and acetic acid (Pfuntner 2011). 
 Peracetic acid is also reported to have very low adsorption to soil (adsorption coefficient Koc of 4) (Pesticide Action Network North America 2014b). Hydrogen peroxide, its co-active ingredient, also  oxidizes on contact, breaking down into water and oxygen. Peracetic acid and hydrogen peroxide,  therefore, degrade quickly and have low persistence in the environment and on food (Azanza 2004). The  Technical Report for hydrogen peroxide may be referenced for further information on the persistence or  concentration of hydrogen peroxide and its by-products in the environment.  Peracetic acid has been found in some instances to have beneficial effects related to environmental  contamination. One study reports peracetic acid to be effective in degrading toxic compounds benzo(a)pyrene and -methylnaphthalene in lake sediments through oxidation of the parent compound (N'Guessan, Levitt, and Nyman 2004). 
Peracetic acid was readily biodegradable during a biodegradation test when its biocidal effect was prevented. Peracetic acid will be degraded in a sewage treatment plant if the influent concentration is not  extremely high (e.g., more than 100 ppm). 
If effluents generated during the production or use of peracetic acid are treated by a waste water treatment plant, no emission of peracetic acid to the aquatic  environment is expected (OECD 2008). 
Acetic acid, the byproduct of peracetic acid, is also highly soluble, has low adsorption to soil (adsorption  coefficient Koc of 117), and biodegrades in water into carbon dioxide and water. Its aerobic soil-half life is  reported as an average of 0.05 days (Pesticide Action Network North America 2014a; Azanza 2004). Thus, it also has very low persistence in the environment. 
The residual amounts of acetic acid on food sanitized  with peracetic acid solutions are expected to be within levels considered acceptable for antimicrobials (Azanza 2004). 
 EPA-registered pesticide product labels for peracetic acid solutions state that they are toxic to birds, fish  and aquatic invertebrates, and instruct users to use caution when applying indoors because pets may be  at risk. 
These labels further instruct not to discharge effluent containing peracetic acid products into lakes, streams, ponds, estuaries, oceans or other waters unless in accordance with the requirements of the  National Pollution Discharge System (NPDES) permit and the permitting authority has been notified in  writing prior to discharge. 
None of the uses permitted under NOP regulations involve direct application  of PAA to effluent, and residual PAA from agricultural and food sanitizing applications is expected to be negligible due to its breakdown during oxidation.

Peracetic acid is used for chemical sanitation of food surfaces and food contact surfaces. The objective of  chemical sanitation is elimination of microbiological threats to human health in the foods we eat. The  microbial load on foods is determined by practices from farm to fork, including on-farm worker sanitary  practices (hand-washing, etc.), animal and poultry husbandry practices (crowding, Salmonella-free laying  hens, etc.), animal and poultry slaughtering practices, rapid cooling, harvested produce storage and pest  control, and the time interval between harvest and consumption or between harvesting and processing. 
Alternative methods that handlers can use to reduce the microbial load on the food raw materials they  receive are limited. Applying heat or steam or fermenting the food can be effective in some situations, but these practices are likely to drastically change the properties of the food. 
 Several alternative materials are allowed in organic handling for sanitizing food surfaces and food contact surfaces: chlorine materials, including calcium hypochlorite, chlorine dioxide, and sodium  hypochlorite; hydrogen peroxide (present in all PAA solutions); ozone; and acidified sodium chlorite. 
Phosphoric acid is allowed for cleaning food-contact surfaces and equipment. Organic acids such as acetic acid (used to make PAA) and lactic acid also can be effective antimicrobials. 
Compared to hydrogen peroxide and chlorine materials, peracetic acid has reported advantages.  Researchers in Florida working with the citrus industry generally believe that peracetic acid is better than  chlorine and hydrogen peroxide for disinfecting fruit while simultaneously reducing fruit blemishes  caused by treatment and maintaining fruit quality, compared to these other sanitizer products .

Peroxyacetic acid is the combination of two important and versatile compounds: hydrogen peroxide and acetic acid. The two chemicals combine to form a new compound, peroxyacetic acid. This is an equilibrium reaction where over a period of hours, peroxyacetic acid is formed in situ by assuming elements of both reagents to form the new compound.

Since peroxyacetic acid is an equilibrium product, it can be formulated to have varying concentrations of hydrogen peroxide or acetic acid; it’s important to note however, that the equilibrium product will still contain a measured amount of PAA. Therefore, many different characteristics can be produced. For example, some FDA formulated products have very high levels of acid and lower levels of hydrogen peroxide; which reduce the possibility of discoloring the skin of either meat or poultry carcasses that are being treated.

Conversely, other formulations may have a higher percentage of hydrogen peroxide that arrest various microorganisms like yeast and molds.

Highly effective against a broad range of microorganisms, peracetic acid is the ideal antimicrobial agent for applications across various industries, including agriculture, food processing, water treatment, pulp & paper, and more.

The primary use of PAA is to sanitize and disinfect food processing operations. PAA is also used to remove pathogenic bacteria strains found in beef/pork/poultry as well as in fruit and vegetables. PAA is the product of choice in food processing because of its ease of use, rapid kill, and breakdown into non-harmful biproducts. More importantly, PAA is known as the “cold” sanitizer and is extremely effective at ambient temperatures. The oil and gas industry uses PAA to protect carbon steel piping and equipment from corrosive attack resulting from sulfide forming bacteria. The product is also used to eliminate harmful hydrogen sulfide (H2S) gas emissions at well sites and is used to control nuisance odors emitted from animal processing plants and wastewater treatment facilitates. Lastly, PAA is the product of choice for cooling tower treatments because of its effectiveness in removing biofilm and its favorable aquatic toxicity profile.

PAA is a two-carbon organic acid that contains lots of oxygen ready for release in the presence of bacteria. The mode of action is oxidation of bacteria cells. The cell walls are quickly destroyed resulting in annihilation of biofilm and bacteria colonies. Unlike hops acid which is only effective against Gram (+) bacteria, PAA is effective at killing both Gram (+) (e.g., lactobacillus) and Gram (-) (e.g., acetobacter) bacteria. Because PAA is a heavy, stable liquid that is very soluble in water, it is many times more effective than conventional oxidizers like bleach, peroxide, and chlorine dioxide. Unlike SO2 and ammonium bisulfite, the byproducts of PAA will not become a food source for bacteria.

Oxygen release
Oxidation of bacteria
Byproducts do not become bacteria food

Benefits of Peracetic Acid
Peracetic acid is regularly used in a variety of industries due to its many benefits. 


Microbes cost industry billions of dollars per year spent in compromised product. Microbes contaminate and spoil finished products – everything from food to water systems to paper and paint products. We’re able to quickly detect and quantitate specific microorganisms. Peracetic acid provides quick results, allowing our customers to act immediately.


Peracetic acid breaks down safely to environmentally friendly residues (acetic acid and hydrogen peroxide) with no toxic byproducts. 


Odor control solutions containing peracetic acid do not require multiple chemicals to generate and are considered a more powerful and stable oxidizer than hydrogen peroxide.





Peracetic Acid and Food Production
Peracetic acid is used for sanitizing of food contact surfaces, sanitizing and disinfecting of animal premises and as a food processing aid for antimicrobial intervention without imparting odors, colors, or flavors to the finished product.

This includes: 

Intervention Chemistry
Fruit & Vegetable Washing
Aseptic Packaging
Sanitizer, Disinfectant, Virucide & Fungicide
Waste Water Treatment & Odor Control
Cooling Towers & Chillers

FDA Food Processing Applications of Peracetic Acid
Compared to competitors’ products, Hydrite’s line of HydriShield™ is effective in food contact applications including meat, poultry, processed and pre-formed meat, processed and pre-formed poultry, fish and seafood, fruits and vegetables, shell egg washing, and sauces or marinades for meat and poultry.


May be used in process water and ice used to spray, wash, rinse, or dip meat carcasses, parts, trim, and organs; and in chiller water or scald water for meat carcasses, parts, trim, and organs.


May be used in process water and ice used to spray, wash, rinse, or dip poultry carcasses, parts, trim, and organs; and in chiller water, immersion baths (e.g. Less than 40o f), or scald water for poultry carcasses, parts, trim, and organs.


May be used in water, brine, and ice for washing, rinsing, or cooling of processed or pre-formed meat products.


May be used in water, brine, and ice for washing, rinsing, or cooling of processed and pre-formed poultry products.


May be used in brines, sauces, and marinades applied either on the surface or injected into processed or unprocessed, cooked or uncooked, whole or cut poultry parts pieces.


May be used in surface sauces and in marinades applied on processed and pre-formed meat and poultry products.


May be used in process water and ice used to commercially prepare fish and seafood.


May be used in process water for washing shell eggs.


May be used in process water and ice used for washing or chilling fruits and vegetables.


May be used as a spray on seeds for sprouting and on edible seeds and nuts.

Peracetic acid has many applications related to the treatment of process water, cooling water and wastewater. These may include: 

The treatment of water used in primary or secondary oil and gass recovery systems to control anaerobic sulfide forming bacteria and aerobic slime forming bacteria
Control of slime forming bacteria and biofouling in recirculating cooling water systems, non-food contact water systems and ornamental or recreation water
Oil and gas used in the treatment of produced water, cooling water, influent systems, retort water systems, irrigation water systems and wastewater

Hydrogen Sulfide Oxidation
Unleashing the oxidative power of Hydritreat SB2216, a Hydrite peracetic acid product, to reduce and remove dangerous hydrogen sulfide (H2S) levels is more effective than traditional treatments of bleach and peroxide. Hydritreat can be used to remove H2S odor in wastewater treatment applications, oil and gas processes, as well as retention ponds and breaks down into non-harmful by-products: vinegar and water.


Effluent Disinfection
Secondary effluent water treatment options showing the positive impact EPA registered peracetic acid has on effluent treated with UV. Used in conjunction with UV, peracetic acid will improve effluent clarity allowing UV to be more effective at lower output giving operators the confidence to control effluent quality during high load and UV maintenance conditions.

Peracetic Acid (PAA) is one of the few sporicidals that can perform this job safely and effectively. The key reason for this is that PAA is an effective sporicide at very low concentrations (less than 1%). Adding to the case of PAA is that the chemical is also listed in <1072> classification as a validated cold sterilant. So, it represents a doubly effective chemistry. When you consider that the only other chemicals validated as both a sporicidal agent and sterilant by the USP <1072> are hydrogen peroxide (H2O2), which is deployed in a vapor form and at high concentration (far over 10%), and Ethylene oxide, you understand the need for a more user-friendly option. PAA at 0.015% concentration in a liquid form can be used for daily low level biodecontamination in aseptic rooms replacing bleach (toxic and corrosive), quaternary ammonium, or other low-level biocides.

Advantages Of PAA
PAA has additional benefits which increase its value as an ideal cleanroom sporicidal agent, including:

The chemical is fully biodegradable (breaks down into oxygen, water, and acetic acid).
It leaves no residual on the surfaces after it evaporates.
It can be validated as a sterilant even at a very low concentration level.
It can be used in both liquid and/or vapor (dry fog) form, is fully compatible with modern cleanroom materials, and is available at a pharmaceutical grade chemical purity level.
FDA and USP guidelines play a big part in developing pharmaceutical activities in facilities all over the world. Developing effective, compliant disinfection procedures for the facilities is where the users of disinfectants sometimes get in trouble. The best course of action for users to save time and money is to follow the recommendations set forth by the USP <1072>, getting the right efficacy, and simplifying the protocols. When considering the risk vs. the benefits, PAA is one of the better choices for cleanroom disinfection, and it is now being used by more and more biopharma companies.

As regulations on chlorinated disinfection byproducts and total residual chlorine become increasingly stringent, peracetic acid (PAA) is gaining in both interest and usage as a water reclamation disinfectant. Here’s what you need to know.
PAA is an organic acid with a strong oxidation potential (1.81 eV) commonly used as an oxidizing agent and disinfectant in industrial applications, such as poultry processing and beverage packing. It is a colorless, organic acid manufactured by the reaction of acetic acid, acetyl chloride, or acetic anhydride with hydrogen peroxide (H2O2) or by direct oxidation of acetaldehyde. It exists in an equilibrium mixture with water, hydrogen peroxide, and acetic acid (Figure 1). It is a stronger oxidant than chlorine and has a wide spectrum of antimicrobial activity (Kitis, 2004).
Currently, most PAA use in water reclamation facilities is driven by the need to consider disinfection alternatives to chlorination or ultraviolet (UV) radiation. Reasons for using PAA include:
•    Concern about disinfection byproducts (DBPs) or environmental impacts
•    Effluent with widely variable water quality
•    Effluent with high color, high total suspended solids (TSS), or high oxidant (chlorine or ozone) demand
•    Sites with limited contact time available
•    Combined sewer overflow (CSO) or other applications where the disinfectant needs to be stored for extended periods
•    Sites where low capital costs are a primary driver
•    Sites where infrastructure supports easy conversion to PAA
•    Sites where chemical dosing rates have increased due to process changes
If chemical disinfection is currently utilized, the capital cost of retrofitting the system for use with PAA is relatively low.
Benefits And Challenges With Utilizing PAA
PAA has several advantages over common disinfection technologies such as chlorination or UV. The efficacy of PAA is high over a wide pH range and is unaffected by high nitrite or low ammonia concentrations, which can fluctuate during secondary treatment. The addition of PAA does not increase the effluent chlorine concentration. Under conditions controlled to prevent contamination and elevated temperature, PAA can be stable in storage for up to a year without degradation, making it advantageous for CSO and other intermittent applications. In many cases, quenching can be eliminated because PAA is less toxic to aquatic species than chlorine and because lower doses are generally required. If chemical disinfection is currently utilized, the capital cost of retrofitting the system for use with PAA is relatively low.

There are disadvantages to using PAA under some conditions. All PAA formulations contain acetic acid, although the amount varies between manufacturers. The acetic acid in the PAA solution may increase effluent biochemical oxygen demand (BOD), so facilities with effluent BOD limitations need to take that into consideration. The cost of PAA is greater than sodium hypochlorite, although some of that cost is offset by reduced dosing and possible elimination of quenching. Finally, while the EPA has approved the use of PAA as a primary disinfectant at water reclamation facilities, each state regulatory agency must separately approve the use of PAA. Figure 2 illustrates the states that have already approved the use of PAA as a primary disinfectant or are in the process of approving it as of late 2017.
State Of The Industry
PAA has been utilized in the agriculture, food and beverage, and medical sterilization industries as a disinfectant since the early 2000s, 1990s, and 1980s, respectively. However, it wasn’t until the fall of 2011 that PAA first was used as a primary disinfectant at water reclamation facilities in the U.S.
A standard method to measure PAA residual concentration does not yet exist; however, PAA residual can be measured using the same analyzer/method as that for total residual chlorine. Still, the effort to develop a method is underway, and the technology for PAA measurement (DPD colorimetry) is already widely used. For online PAA residual measurement, amperometric probes are commercially available but have limited field demonstration data in wastewater applications.

Peracetic acid (PAA) was first registered as a disinfectant in 1985 by the EPA. 
PAA is produced by combining acetic acid (vinegar) and hydrogen peroxide.  
The result is a peroxide version of acetic acid (vinegar) that has a very distinctive and a pungent vinegary smell. 

It is a weak acid compared to acetic acid but can be highly corrosive if not used at the appropriate dilutions. 
Peracetic acid is a versatile chemical that can be used in a variety of applications with its main use as a disinfectant product in food and beverage processing/producing plants due to the fact that it leaves no harmful residues and decomposes into harmless by-products.

As a cleaner, peracetic performs poorly as it lacks detergency properties.  
As alluded to in previous blogs, you may wonder whether increasing the concentration of this acid would benefit its cleaning. 
The answer in short is: No. 
A higher concentration would not increase its cleaning abilities and in fact would lead to an increase in corrosiveness.
As a germicide, peracetic acid shows fairly strong efficacy against a broad spectrum of pathogens. 
Like many disinfectants, the temperature, pH and concentration all play a significant role in determining the antimicrobial properties. 
It is bactericidal at 10ppm, fungicidal at 30 ppm and virucidal at 400 ppm in a 5 minute contact time. 
Furthermore, it is sporicidal at concentrations of 3000 ppm. 
It is more effective at slightly higher temperatures and its germicidal activity increases at higher pH ranges.

Combinations of PAA and hydrogen peroxide further boost the efficacy profile, as this blend can prevent the formation of biofilms on hard surfaces. 
The method by which PAA attacks pathogens is through the reaction with the cellular walls. 
This leads to breakdown of cell membranes and cellular death due to cell content leakage. 
An issue regarding PAA usage is its stability. In the presence of water, it breaks down quickly. This would have a direct affect on the viability of the product over time.

Peracetic acid’s safety profile can also be closely correlated to its concentration. 
The higher the concentration, the worse the safety profile is. 
For example, an in use solution of PAA of 5% has relatively low oral toxicity at this dilution. 
However, respiratory issues, including occupational asthma development associated with PAA have been reported.

Further, it can strongly sensitize respiratory organs and cause mucus membrane inflammation. 
Furthermore it is important to be weary of skin and eye exposure as it can cause irritation. 
Overall, peracetic acid proper care needs to be taken in its use.

The environmental profile of peracetic acid once again depends on the concentrations encountered. 
At high concentrations, it can be toxic. 
However, in use concentrations do not pose major threats to the environment. 
Furthermore, PAA is a readily decomposable substance and breaks down to products that are not considered harmful to the environment.

This is how we would rate peracetic acid disinfectants based on the key decision making criteria:

• Speed of Disinfection  
At a 5 minute contact time for killing bacteria and viruses, peracetic acid is fairly rapid in killing. 
However it carries a 30 minute sporicidal contact time, which is unrealistic unless used for soaking applications.

• Spectrum of Kill  
Certain temperatures, pH, and concentrations affect the efficacy of peracetic acid.
At 3000 ppm, peracetic acid can kill all microbial life whereas at 10 ppm, it only kills bacteria.

• Cleaning Effectiveness 
Peracetic acid has poor cleaning capabilities.

• Safety Profile 
Peracetic acid has a safe oral toxicity, however, it is sensitizing to the respiratory tract and irritating to skin and the eyes.

• Environmental Profile
Peracetic acid readily decomposes and its primary and secondary products are all deemed non-harmful to the environment.

• Cost Effectiveness 
Peracetic acid is readily available from various manufacturers and can be found in both concentrated and ready-to-use formats.

Peracetic Acid, also known as peroxyacetic acid or PAA, is an organic chemical compound that is used in a mixture with acetic acid and hydrogen peroxide in water.

It is a colourless liquid that has a strong vinegar-like odour that can be smelt at very low levels. It is a very powerful oxidant, which means that PAA removes electrons from other reactants. PAA chemical is highly reactive but breaks down to acetic acid (vinegar) and water so it leaves no harmful residue, which makes it the chemical of choice when looking for a food-safe antimicrobial.

The process for using peracetic acid as a disinfectant can simply be defined by a combination of hydrogen peroxide, acetic acid and water. PAA functions as a disinfectant by oxidizing the outer cell membrane of microbes. The stronger the solution of Peracetic acid, the more effective it is as an antimicrobial, but the more dangerous to everyone around. This highly biocidal oxidiser removes surface contaminants, such as viruses and spores, in many different ways. 

Where is it found
Treatment of bottles and beverage containers prior to filling
Poultry, meat, seafood, fruits, vegetables and other food items to prevent foodborne illnesses
Disinfection of medical devices in hospitals and manufacturing
Wastewater treatment facilities during water purification process prior to discharge
Agriculture storage - For making an area sterile between seasonal crops
Fracking, gas and oil operations as antimicrobial
Eliminate powdery mildew on plants
What are the dangers of Peracetic Acid?
According to NIOSH. Concentrations of 15% or higher, also give rise to fire and explosion hazards and reactivity issues. It is important to ensure that training and safety precautions for peracetic acid are in place.

Another major concern is that peracetic acid has a pungent vinegar type odour, even at low levels. If you are working around PAA and do not smell it, it's more than likely it is due to olfactory fatigue. Olfactory fatigue is also known as nose blindness or odour fatigue. While making sure the items you're disinfecting are safe, make sure to keep track of peracetic acid safety where you work.

Eye irritation: eye damage after prolonged exposure

Respiratory distress: fluid in the lungs after high level of exposure (edema)

Nose and throat irritation

Asthma associated with workplace exposures

Skin irritation dermatitis

Data on animals showed: hemorrhage, edema, and pulmonary consolidation

Regulations/ Guidelines for Peracetic Acid
Exposure limits and guidelines when using peracetic acid disinfection have been set by a number of national agencies including the following.  Make sure to follow these for proper PAA safety and training of staff:

Best Safety Practices for Peracetic Acid
Monitoring PAA
It is highly recommended to use a combination of continuous fixed area monitoring and portable area monitoring to find danger zones throughout any facility that uses Peracetic Acid.

Continuous fixed area monitoring is recommended in the following areas:

Near concentrated PAA storage tanks, dilution lines, and pump stations

Any area where employees have experienced symptoms or known risks are present for exposure - endoscopic units

Portable monitoring is recommended as a daily routine through danger zones combined with any additional spot checks needed throughout the day.

Bleaching agent for food starch. Peracetic acid is a component of antimicrobial washes for poultry carcasses and fruit.
Peracetic acid (also known as peroxyacetic acid, or PAA), is a organic compound with the formula CH3CO3H. 
This organic peroxide is a colorless liquid with a characteristic acrid odor reminiscent of acetic acid. 
It can be highly corrosive. Peracetic acid can be used as a bleaching agent especially for Kraft pulp. 
It is used at weakly acidic pH and relatively low temperature. 
It is a relative efficient and selective bleaching agent, and it is often used as an alternative to chlorine dioxide and elemental chlorine in totally chlorine free bleaching sequences (TCF). 
It is however relatively expensive, and is difficult to store due to its high reactivity. 
This has limited its use. Peracetic acid is a much weaker acid than the parent acetic acid, with a pKa of 8.2. 
Peracetic acid is an ideal antimicrobial agent due to its high oxidizing potential. 
It is broadly effective against microorganisms and is not deactivated by catalase and peroxidase, the enzymes that break down hydrogen peroxide. 
It also breaks down in food to safe and environmentally friendly residues (acetic acid and hydrogen peroxide), and therefore can be used in non-rinse applications. It can be used over a wide temperature range (0-40 °C), wide pH range (3.0-7.5), in clean-in-place (CIP) processes, in hard water conditions, and is not affected by protein residues

The application that describes the determination of AcOH and PAA in a single titration using aqueous NaOH as titrant. The large difference between the pKa values of AcOH (4.75) and PAA (8.2) enables the determination of both species using a single titration.


Peracetic acid (also peroxyacetic acid, PAA, CH3COOOH) can be obtained by mixing hydrogen peroxide with acetic acid (AcOH). Because of its strong oxidizing character, PAA is often used as bleach or disinfectant. The main field of application is the sterilization of plastic bottles in the bottled beverage production. Upon mixing hydrogen peroxide and acetic acid, the following equilibrium is slowly settled:


The formation of this equilibrium is very slow but can be accelerated by the presence of strong acids. Solutions with PAA contents between 2.5 and 40 % are commercially available. A dilution of the mixture with water leads to a new equilibrium with a lower PAA content.

The determination of PAA is commonly performed by redox titrations. PAA oxidizes iodide to iodine, which is then titrated with thiosulfate. The hydrogen peroxide, which is always present in the solution needs to be titrated first, e.g. with potassium permanganate, because it interferes with the iodometric titration. Apart from the high complexity, this method has the drawback that it relies on the use of sulfuric acid, which catalyzes a shift of the equilibrium to lower PAA contents during the sample preparation.

Vaporized peracetic acid (VPA) has become a game-changer in medical device sterilization, providing for a room-temperature process designed to preserve newer device materials and components.

Mason Schwartz, Revox Sterilization Solutions

(Image courtesy of Revox Sterilization Solutions)

Advancements in medical device manufacturing have yielded products that are either heat-sensitive or easily degradable. Many materials that would otherwise be ideal for product design cannot withstand traditional sterilization methods such as steam, dry heat, hydrogen peroxide (VHP), ethylene oxide (EtO) or gamma/E-beam irradiation. This limits overall product innovation and, if not considered before product design, interferes with project progression, objectives, and product launch.

Liquid or vapor
Peracetic acid (PAA) is formed by the reaction of acetic acid and hydrogen peroxide (H2O2); these compounds exist in equilibrium and their eventual decomposition results in oxygen (O2), carbon dioxide (CO2) and water (H2O).

The room-temperature VPA process greatly improves material compatibility over other sterilization methods such as hydrogen peroxide (VHP), ethylene oxide (EtO), and gamma/E-beam irradiation. Liquid peracetic acid (PAA) and vaporized peracetic acid (VPA) are highly biocidal sterilants that maintain efficacy in the presence of organic soil while removing surface contaminants.

Through extensive testing of more than 100 materials, VPA has shown high material compatibility. For example, the VPA method can safely sterilize products that would normally be damaged by a liquid chemical, even copper, which is known to oxidize from liquid PAA. A product containing liquid copper was exposed to the VPA process in 10 repeated four-hour cycles, only showing a slight dulling of the original gloss. Tests have also been successfully conducted using multiple sterilization cycles on thermoplastics, thermosets, adhesives, batteries, and bioabsorbables.

Bioabsorbable implants such as internal drug delivery mechanisms, stents, vascular grafts, and scaffolds for tissue engineering rank among the latest cutting-edge medical device categories in the world. They are also among the most heat- and moisture-sensitive products. Sterilizing products like these requires a stable gaseous chemical agent that will not degrade the product. The ethylene oxide (EtO) process typically operates at 40 degrees Celsius, and hydrogen peroxide gas phase sterilizers range between 28 and 60 degrees Celsius, whereas VPA sterilization processes between 18 degrees to 30 degrees Celsius.

Other advantages
VPA’s non-toxic, sterile processing solution leaves behind no harmful residuals, providing not only a safer work environment for employees but a safer product for patients. With VPA breaking down into carbon dioxide, oxygen and water, the VPA process is noncarcinogenic, nonexplosive/flammable, and requires no external ventilation. It can be integrated directly into the on-site manufacturing process, reducing transportation and inventory costs associated with other contract sterilization methods.

Sterilization process time can vary greatly, depending upon the product being sterilized and including the pre-sterilization and post-sterilization aeration periods and external quality processes. Because it requires no pre- or post-aeration, VPA can significantly reduce the overall process time and reduce inventory costs. It also provides the option to bring sterilization on-site, eliminating the inefficiencies associated with off-site sterilization.

Peracetic Acid is a kind of purposes strong oxidizer very widely, and it can be used as the SYNTHETIC OPTICAL WHITNER of paper, paraffin, timber, starch.Medicine industry is used as drinking-water, food and prevents the sterilizing agent of transmissible disease.Organic industry is as oxygenant and the epoxidizing agent of manufacturing propylene oxide, glycerine, hexanolactam etc.

Where is peracetic acid used?
Workplaces where peracetic acid is used include:

·         Meat and poultry processing plants

·         Dairy and cheese processing plants

·         Healthcare facilities

·         Food establishments

·         Beverage plants, including breweries and wineries

·         Paper and pulp facilities

·         Water treatment facilities

·         Cooling water towers

Peracetic Acid or Peroxyacetic Acid is a strong oxidizer useful for high level disinfection and sterilization. 

Peracetic acid is used as a delignifying and brightening agent in the production of environmentally friendly TCF and ECF pulps. 

Peracetic acid is an excellent product for post-bleaching of pulps.
High and consistent pulp brightness of the pulp, with good stability, can be achieved via post-bleaching using Peracetic acid in storage towers of bleached pulp. 
Post-bleaching is an outstanding tool for producing a fiber quality that meets downstream needs. 
Mills previously having problems with brightness variation, reaching brightness targets, post-bleach yellowing, and cleanliness of pulp or paper have successfully applied it.
Additionally, a reduction in consumption of optical brighteners and biocides can be obtained with improved retention of wet end chemicals. 
The overall costs in the pulp and papermaking process will be reduced with the help of Peracetic acid post-bleaching.

Peroxyacetic acid (Peracetic Acid, PAA; CH3CO3H) is a sanitizing agent widely used in the food and brewing industries and increasingly in the wine industry for its ability to efficiently kill microbes and sanitize surfaces “on contact” (Orth 1998). 
Despite its killing power against microbes, tank rinsing following sanitation is not required (Heritage Systems 2005) as the diluted concentrations (2.5-15%) at which it is used leaves low residual PAA (3-5 ppm), found harmless to human consumption (Orth 1998), and breaks down to form acetic acid, oxygen, and water (Kramer 1997). 
The mechanism of microbicide is through the formation of hydroxyl radicals, which rapidly oxidize a variety of organic materials, including lipids, ionic protein bonds, sulfhydryl groups, and cysteine disulfide bonds (disrupting protein structure), killing cells with ruthless efficiency even at low concentrations; this is the same oxidative antimicrobial mechanism exhibited by hydrogen peroxide, but PAA has a much higher oxidative capacity at much lower concentrations (Heritage Systems 2005). 
As such, it displays efficient killing capacity against gram-positive and gram-negative bacteria, yeasts, molds, and algae (Kramer 1997) at a broad temperature (≥ 34˚F) and pH range (≤ pH 8.5) (Heritage Systems). 
It diminishes these populations within one minute of contact (Kim et al. 2007), but is less effective at depleting bacterial biofilms on contact without prior cleaning (Rossoni and Gaylarde 2000). 
Claims are made both ways as to whether acetic acid formed by the breakdown of PAA is at concentrations significant to influence the acetate concentration of wine contacting unrinsed surfaces sterilized with PAA (Heritage Systems 2005).

Application in Wine:

PAA is gaining popularity as a sanitizing agent in the wine industry for its broad microbicidal capacity, and rapid, on-contact efficacy under a range of conditions. It can be used to sanitize a range of surfaces and equipment, including tanks, pumps, lines, and filters (Orth 1998), and is non-corrosive to stainless steel at the dilute usage concentrations. 
Moreover, it is a non-chlorinated cleaning agent, so will not form trichloroanisole (TCA; “cork taint”), which is formed through chlorine–phenol reactivity and enymatic conversion by molds, and also will not add salinity to process water, causing waste disposal problems, and therefore does not carry many of the problems posed by other sanitizing agents, such as trisodium phosphate (TSP) (Heritage Systems, 2005).

Peracetic Acid (PAA), the antimicrobial properties of peroxyacetic acid, was first described in 1902. However, it was more than 50 years before PAA was “rediscovered” and commercially introduced. The long lag time was likely caused by a lack of understanding of how to stabilize PAA solutions and by reports of spontaneous decomposition of highly concentrated solutions. Today, PAA has become a common choice of sanitizer/disinfectant for breweries because of its broad antimicrobial activity and its “compatibility” with beer.

PAA is a clear liquid shipped in specially vented containers similar to those used for bleach and hydrogen peroxide. In concentrate and strong-use solutions, it exhibits a strong, characteristic odor reminiscent of acetic acid or vinegar, especially when handled or agitated. PAA solutions are produced by mixing acetic acid and hydrogen peroxide in an aqueous solution, often assisted through a sulfuric acid catalyst. PAA has a very high oxidation potential and is therefore an ideal antimicrobial agent. PAA has an extremely broad killing spectrum and is effective against bacteriophages and spores. PAA is a very effective cold sanitizer and can be used over a wide range of temperatures (0°C–40°C) as well as a wide range of pH (1–7.5). It is non-foaming and therefore an excellent choice for use in cleaning in place applications.

PAA is relatively unstable and breaks down readily into acetic acid (acetate), water, and atomic oxygen. This form of oxygen poses no risk of oxidation to beers that come into contact with it. These breakdown products are environmentally friendly and PAA is certified for use in the production of organic beers. Brewers appreciate the effectiveness of PAA; however, it must be handled carefully because it is highly concentrated and can cause burns

Peracetic acid
PAA is only available in acidified, stabilized solutions with hydrogen peroxide and acetic acid. The compositions and strengths of the products vary, with active concentrations of PAA typically ranging 5-15 percent/L.

This relatively broad concentration range is the first thing to consider when planning water treatment. PAA products are used in most of the rearing phases, for egg disinfection and water quality control in hatcheries, raceways, growout tanks and delivery ponds. PAA can efficiently control parasites, reduce dinoflagellates and suppress fungal infections related to the handling of broodstock.

Treatment efficacy
peracetic acid
Introducing diluted PAA to culture units over an hour period ensures even addition and avoids local peak PAA concentrations and drops in pH.
PAA has proven effective in controlling the parasites Ichthyophtirius multifiliis (ICH), which causes white spot disease, and Ichthyobodo necator-costia in fish, and the mold Saprolegnia on eggs.

Prophylactic treatment of eggs is done by mixing PAA with water and adding this solution to the inlets of egg trays. Treatment concentrations applied to juveniles, fingerlings and grow-out sized fish are relatively low, in the range of 2-10 mL/m3, depending on water quality and the PAA product used. This corresponds to PAA concentrations on the order of 0.3-1.5 mg/L.

Due to the highly reactive properties of PAA, residual concentrations rapidly decline – especially in water rich in organic matter. This is an issue to take into account when using PAA. If a system contains large pools of organic matter, higher PAA dosages are needed.

Using a low-dose PAA in organic-rich water can result in degradation of the chemicals within a few minutes, which has implications for the locations of PAA applications. If added at the inlet to a long raceway, for example, the chemical may degrade before it reaches the end of the raceway. In such cases, the use of multiple sites of application or repetitive dosing is recommended.

System design addressing tank configuration, flow and the presence of biofilters must also be taken into account.

PAA application
Choosing the correct dose of PAA depends on the water composition, fish size, temperature and system design. Treatment protocols include pulse dosage, where the chemical is added once on a daily basis. They can also include repetitive additions or continuous low dosage over prolonged periods.

In systems with low organic matter content – hatchery facilities and well water ponds, for example – continuous PAA application can be a feasible solution to control water quality. Continuous addition relies on dosage pumps and adjustment of dose according to flow and makeup water. Recent experiences at some Danish fish farms that apply prolonged, continuous daytime addition of PAA showed that the usual outbreaks of white spot disease were avoided.

Environmental impacts
Due to the low doses applied and rapid degradation of PAA, residual amounts of the chemical appear at very low levels, if present at all, in effluents. With half-lives on the order of a few minutes, PAA products degrade within ponds, raceways or constructed wetland, leaving no residues to enter receiving water bodies.

The degradation product of PAA is acetate. Harmful disinfection by-products are not formed when using PAA, making it a benign disinfectant when compared to chloramine-T, sodium chloride, formaldehyde and copper sulphate.

Worker safety
PAA products are all acid stabilized and hence corrosive. All types of handling require precautions such as safety goggles and acid-resistant gloves. Compared to formalin, which is a severe nasal/pharyngeal irritant and considered carcinogenic, PAA is relatively harmless.

PAA products have a pungent smell and should be stored in a place with ventilation. 
Containers for PAA products have pressure caps, and PAA should not be decanted from large to smaller jars.

Organic requirements
Several Danish rainbow trout producers have been certified organic. According to European Union requirements, at least 50 percent of the ova/fry used should be reared organically. 
In January 2016, all organic fish production has to be based on certified organic fry. 
This has put even more focus on optimizing water quality and implementing disinfectants in an organic context to replace formalin.

Low-dose, continuous PAA application has shown promising results for a couple of organic fry producers. 
The treatment procedure is effectively controlling white spot disease in the critical summer period, which normally sees the addition of formalin, and the application has not led to the discharge of unwanted chemical residuals.

Periodic outbreaks of latent diseases such as rainbow trout fry syndrome, red mouth disease or furunculosis are expected to be less frequent when water quality is good and kept stable under PAA treatment.

Issues, improvement

In hatcheries, egg trays, tanks and raceways can be sanitized with PAA on a daily basis.
Optimal application of PAA is not easy. The recommended dosage guidelines depend on the product applied and the system to be sanitized. 
As a rule of thumb, a concentration of 0.2-0.5 mg PAA/L is typically sought. 
This concentration is very low, and due to the fact that no test kits are available, expected PAA concentrations are often overestimated compared to actual concentrations.

In the case of controlling white spot disease, PAA application has demands other than those for baths of formalin or sodium chloride. 
The life cycle of the ICH parasite that causes white spot disease includes a free-swimming stage – theronts – that can be eliminated by disinfectants. 
Since the theronts are liberated throughout the day, continuous chemical application is needed.

In oligotrophic aquaculture systems, this can be achieved by dripping PAA into the distribution channel that leads to the inlets of the ponds. 
This has proven effective in some cases, but when system water becomes rich in organic matter, higher dosages – which are more difficult to adjust – are needed.

Continuous PAA application has also been applied to control unwanted pathogens in recirculating aquaculture systems. 
Preliminary observations show the potential of this and also highlight a potential need for base adjustment if water reuse is significant.

Troublesome parasites such as gill amoebae sometimes cannot be sufficiently controlled on farm by current practices for applying PAA. 
This often correlates with insufficient solids removal and increased organic matter content. 
It is expected that hydrogen peroxide, alone or in combination with PAA, can be a complementary chemical agent to ensure proper water quality.

PAA is relatively safe to handle and degrades rapidly, making it beneficial from both worker safety and environmental perspectives. 
The reactiveness, mode of action and rapid decay, similar to that of ozone, are challenges for aquaculturists and set high requirements for proper dosing.

Recent developments within the industry have accelerated better water treatment practices that now include daily pulse additions, as well as continuous, low-dose applications. 
As organic aquaculture systems place added focus on rearing conditions and water quality, PAA is expected to have a pivotal role in the future development of organic aquaculture.

Disinfectant is projected to be the fastest-growing application of peracetic acid. A key factor for the growth of this segment is the high demand for peracetic acid-based disinfectant in the food & beverage, healthcare, wastewater treatment, and pulp & paper industries. Peracetic acid is largely used in the disinfection of medical supplies in the healthcare industry. In the pulp & paper industry, it is used to prevent biofilm formation. Peracetic acid-based disinfectant is also used in the water treatment industry to treat wastewater and sewage water. It is projected to have a high demand in the water treatment industry and is mostly used for purification and disinfection of water treatment systems.

Peracetic acid is a colorless,sometimes slighty yellow, solution. Its odor refers to vinegar. Its chemical formula is CH3CO3H. It is used specially for disinfection, due to its sterilizer, fungicide, viricide, bactericide an sporicide properties.

Peracetic acid is powerful disinfectant used in food and beverage industry, for aseptic packaging (PET), in laundries, in animal health care, as an anti-slime agent, for wastewater treatment and as a sterilant in medical applications. Oxidizer for chemical synthesis.

The science of oxygenation is a quiet but powerful force, present in processes everywhere we look. As leading manufacturers and suppliers of hydrogen peroxide, our knowledge of oxygenation and oxidative chemistry is developed, backed and delivered by engineers, chemists, business people, and technicians with decades long accumulation of experience. A fundamental way to deliver oxygen, by organic peroxide, our peracetic acid is a liquid mix of hydrogen peroxide and acetic acid (vinegar) that brings to food processing, beverage packaging, and environmental and water treatment, a clean, beautiful set of solutions.

Peracetic acid is a versatile oxidizing agent that dissolves easily in water and decomposes into non-toxic by-products. Evonik is one of the leading producers of peracetic acid and has developed a wide offering of high quality products, ranging in concentration from 5% to 40% peracetic acid in equilibrium solution.

The different concentrations are used in chemical synthesis, bleaching, sanitization, disinfection and sterilization across a variety of industries, including food and beverage, environmental remediation, industrial cleaning and sanitization, and oil and gas production.

Today, a highly efficient agriculture plays an important role due to increasing demand of a growing population. In open fields, there is a trend from traditional flood irrigation to more efficient drip irrigation. A major issue in drip irrigation is the clogging of tubes and emitters due to biofilm formation. In greenhouses, besides the drip irrigation system, there is an additional need to fight pathogens which can be found on any surface. Also, it has been shown that disinfection of fruits or vegetables can extend their shelf life.

Solutions of peracetic acid have been proved to be a highly effective and environmentally friendly biocide in agriculture. Pulse cleaning of drip lines in the absence of plants, disinfection of tools, tables and containers as well as washing of harvested goods with peracetic acid are typical examples of the broad range of possible applications.

The main applications are:

Washing water for potatoes
Washing water for fruits
Irrigation water (surface, rain and spring water)
Greenhouses and other horticulture purposes
The concentration of peracetic acid depends on the specific requirements in the respective application.
It is advisable to adapt the concentration on the basis of corresponding microbiological tests. The product is suited to kill harmful organisms such as Soft Rot (Erwinia Carotovora) and Brown Rot (Ralstonia Solanacearum). After disinfection peracetic acid decomposes into ecologically harmless residues such as water, oxygen and acetic acid.

We offer concentrated peracetic acid formulations with a broad spectrum of efficacy against virus, bacteria, fungi and spores. They are highly effective in very low concentrations even at low temperatures and/or in presence of organic impurities. Applications
include general surface and equipment disinfection, treatment of water supply systems and thermal fogging.

In surface disinfection the surfaces are cleaned and disinfected to avoid diseases in livestock.

The product is applied by mechanical sprayers or pressure washers. Water systems very often contain bacteria. Sanitizing cleans the system and eliminates growth of bacteria.
Thermal fogging is the preferred procedure to disinfect buildings, animal housings and inside areas that are difficult to access. It requires special fogging equipment.

Hydrogen peroxide and peracetic acid for the aseptic food & beverage industry

From a morning orange juice or glass of milk to a rejuvenating energy drink, we all rely on beverage and dairy manufacturers to ensure that the drinks we enjoy are not only refreshing, but also safe to consume. Major beverage and dairy manufacturers are challenged to find easy-to-use and cost-effective chemistries to treat harmful microorganisms encountered during the packaging process.

From closure systems to bath, spray or vapor sterilization of cartons or PET bottles, Evonik offers a robust portfolio of peracetic acid and hydrogen peroxide based sterilants and sanitizers to meet the evolving demands of low-acid, high-acid aseptic and extended shelf life applications in the beverage packaging market. Evonik's hydrogen peroxide and peracetic acid sterilants provide optimal sterility that meet your aseptic beverage packaging needs, yet have minimal environmental impact, by breaking down into benign by-products after use.

Aseptic packaging is used to protect food and beverages all along the supply chain. It guarantees a high quality of the packed food stuff combined with a long shelf life. As consumer demand grows for preservative-free ‘natural’ beverages and for products with additional benefits, nowadays a vast variety of food and beverage products are aseptically packaged in cartons, pouches, cups or bottles. Aseptic packaging utilizes hydrogen peroxide or peracetic acid for the sterilization of the packaging material and machines and enables the introduction of gently bottled beverages without additional thermal stress or added preservatives. .

Humankind has been influencing its environment for thousands of years, but with the advancing industrialization of the 19th century, a new era also began for nature.

After the negative influences of human actions have become more and more drastic, it became obvious that damaging the environment sooner or later would also have a significant impact on humans themselves. As a result, there was a slow process of rethinking how to deal with the environment. Sustainability becomes more and more important, especially in Europe there are a number of laws designed to minimize the negative environmental impact of our actions.

There are various limit values, for example, for waste gases and wastewater, which must be complied with.At this backdrop, hydrogen peroxide and peracetic acid have been proven to be two of the most versatile, reliable and environmentally compatible oxidation agents. The relative safety and convenience of the use as an oxidizing agent opens up various application areas with a direct impact and beneficial effect on the environment, such as:

Waste water treatment
Soil remediation and groundwater treatment (Link to former PXC website - Persulfates)
Treatment of recycling water
Reduction of germs (e.g. legionella) in cooling water
Air pollution control
The unique chemical properties of hydrogen peroxide as well as its ecological friendliness predestinate this chemical for an extensive use in a variety of environmental applications. There are numerous examples where hydrogen peroxide helps to prevent or reduce negative impacts on the environment.

Furthermore, hydrogen peroxide is often regarded as a true “green chemical”. In contrast to many other red-ox agents, hydrogen peroxide introduces no additional substances other than water into the reaction system. An excess caneasily be decomposed into water and oxygen, not interfering with subsequent reaction steps.

In case of peracetic acid (PAA) the degradation or additionally derived product is acetic acid (AA), which is readily biodegradable in water and not bioaccumulative.

Despite its high reactivity, pure hydrogen peroxide and peracetic acid products from Evonik decompose very slowly and, if kept under optimal conditions, can be stored for years. Decomposition can be accelerated by high pH values, high temperatures, UV-irradiation, the presence of transition metal salts and other impurities. Decomposition of hydrogen peroxide and peracetic acid is a quite complex process, which involves formation of various free radicals. In some applications (soil remediation) the decomposition of these oxidizers can be used to enhance performance.

While many biocides are effective, many also contaminate ground water and drinking water wells while they work. As leaders in the supply of chemistries for hydraulic fracturing water treatment, Evonik has worked tirelessly to answer this need by using peracetic acid (PAA), a safe chemical that was already established in the healthcare and food processing industries, and reformulating it for energy-production applications.

A mixture of high-purity hydrogen peroxide and acetic acid treated with a proprietary purification process and a small amount of chemical stabilizer, ATAMAN has found PAA to be an oxidizing biocide that rapidly destroys aerobic and sulfate reducing bacteria while decomposing into environmentally benign byproducts, thus minimizing risk to the environment and human health. And minimal risk to the environment and health is a maximum win in our book.

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