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).
- Heritage Systems. 2005. Advantages of Using Peroxyacetic Acid (PAA) in Winery Sanitation Operations [Technical Product Information]. Napa, CA: Heritage Systems, Inc.
- Kim H, Ryu JH, Beuchat L. 2007. Effectiveness of Disinfectants in Killing Enterobacter sakazakii in Suspension, Dried on the Surface of Stainless Steel, and in a Biofilm. Applied and Environmental Microbiology 73(4):1256-1265.
- Kramer JF. 1997. Peracetic acid: A new biocide for industrial water applications. Materials Performance 36 (8):42-50.
- Orth R. 1998. The importance of disinfection for the hygiene in the dairy and beverage production. International Biodeterioration & Biodegradation 41:201-208.
- Rossoni EMM, Gaylarde CC. 2000. Comparison of sodium hypochlorite and peracetic acid as sanitizing agents for stainless steel food processing surfaces using epifluorescence microscopy. International Journal of Food Microbiology61: 81-85.