Peracetic acid (PAA) – often use in non-chlorine based bleach, disinfectants and sanitizers.

Peracetic acid (CH3COOOH) is considered a more potent biocide than hydrogen peroxide, being sporicidal, bactericidal, virucidal, and fungicidal at low concentrations (<0.3%) . PAA also decomposes to safe by-products (acetic acid and oxygen) but has the added advantages of being free from decomposition by peroxidases, unlike H2O2, and remaining active in the presence of organic loads. Its main application is as a low-temperature liquid sterilant for medical devices, flexible scopes, and hemodialyzers, but it is also used as an environmental surface sterilant .

Mode of Action - Only limited information is available regarding the mechanism of action of peracetic acid, but it is thought to function similar to H2O2  and other oxidizing agents, i.e., it denatures proteins, disrupts cell wall permeability, and oxidizes sulfhydral and sulfur bonds in proteins, enzymes, and other metabolites.

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.

Microbicidal Activity - Peracetic acid will inactivate most 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%)654.

Last Edited By: Matt Morris and David Newman Oct 24 15 2:02 PM. Edited 1 time.