Peracetic acid (PAA), also known as peroxyacetic acid and ethaneperoxoic acid, is a clear, colorless organic acid with a strong pungent (i.e., vinegar-like) odor. PAA is primarily used as a sanitizer during the processing and handling of meats, poultry, seafood, fruits, and vegetables, as well as the bottling of beverages. Various types of commercially available formulations are used to:
According to USDA, PAA preserves flavor, color, texture, and nutritional value by preventing microbial and enzymatic deterioration of the product1. While a number of sanitizers are permitted for use with food products and food contact surfaces, PAA remains a popular choice due to its numerous benefits. Given growing public health concerns regarding “superbugs,” a key advantage to the use of PAA is the lack of microbial resistance2. Unlike other sanitizers, microorganisms do not develop resistance to the effects of PAA. Additionally, the nutritional aspect of a food product is not altered by the sanitation process because rinsing in PAA does not result in a significant loss of water soluble vitamins.
PAA decomposes relatively quickly into water, oxygen, and acetic acid (the acidic component of vinegar), making it an environmentally friendly disinfectant that does not leave a residue on the food product or in the environment3. As a result, rinsing with potable water following sanitation is not required for many applications.
Its efficacy over a wide temperature (0- 40 °C) and pH (3- 7.5) range allows for the sanitation of products and equipment normally held below ambient temperature. PAA also allows for clean-in-place (CIP) processes and is unaffected by protein residue.
PAA acts as a quick and effective sanitizer by oxidizing and denaturing the outer membrane of microorganisms, such as bacterial cells, endospores, yeast, and mold spores. It is also capable of irreversibly disrupting the function of peroxidase and other enzymes that are responsible for the discoloration and degradation of fresh fruits and vegetables. In other words, PAA helps to preserve the appearance and flavor of foods, as it disinfects them.
The strong oxidizing properties that make PAA so effective also present challenges for handling the substance. Concentrated PAA is explosive and can be an irritant to the skin, eyes, and mucous membranes over sufficient durations and concentrations. As a result, PAA is diluted to a safe, yet effective, concentration that can be handled more easily prior to use in food processing and handling facilities. Federally approved sanitizing PAA solution concentrations range from 80 to 220 parts per million (ppm), depending on formulation and the application.
PAA is regulated by FDA and approved for direct contact with food4, food processing equipment and utensils, and other food contact surfaces5. Specifications regarding the acceptable PAA formulations are detailed in the regulations. Under the USDA National Organic Program (NOP), PAA is permitted as an ingredient in or on processed products labeled as “organic” and for use as a sanitizer and disinfectant for facilities and equipment related to the production of organic crop and livestock6.
1 See USDA Peracetic Acid Handling/Processing, available at https://www.ams.usda.gov/sites/default/files/media/Peracetic%20Acid%20TR%203_3_2016%20Handling%20final.pdf.
2 See World Health Organization (WHO) Antimicrobial Resistance Fact Sheet, available at http://www.who.int/mediacentre/factsheets/fs194/en/.
3 The rate of PAA decomposition will vary based on solution formulation, temperature, pH, and other factors.
4 See 21 C.F.R. § 178.1010.
5 See 21 C.F.R. § 173.315.
6 See 7 C.F.R. § 205.600-.607.