Impact of total suspended solids on disinfection efficacy of peracetic acid against Salmonella javiana.

Abstract

Peracetic acid (PAA) is frequently utilized in poultry processing as a microbial-control solution to reduce the presence of pathogens in poultry products. Although numerous studies have investigated the influence of acid concentration on microbial inactivation, only a limited number of studies have been documented regarding the effect of total suspended solids (TSS) on the potency of PAA against Salmonella. This study examines the impact of varying TSS concentrations (ranging from 40 to 500 mg/L) on the effectiveness of PAA in reducing Salmonella. At lower pH values (3.6, 6.0, and 7.0), PAA at 30 mg/L achieved complete disinfection of Salmonella in 60 seconds, while at higher pH values (8.0, 9.0, and 10.0), disinfection was faster, occurring within 30 seconds. PAA consumption varied by pH, with higher consumption at neutral and basic pH. Increasing TSS at a fixed pH of 9.5 reduced the antimicrobial efficacy of PAA, with higher TSS concentrations leading to less reduction in Salmonella compared to lower TSS levels over a 10-minute exposure. However, with longer contact times, antimicrobial efficacy improved. The study showed that complete elimination of Salmonella was achievable when TSS levels were less than 40 mg/L, and the disinfection process became significantly faster at TSS levels of 0 mg/L. It was suggested that this phenomenon might occur because the presence of solids could facilitate the accumulation of bacteria as a defense mechanism against disinfection, leading to the decreased efficacy of PAA. These showed that increase in TSS levels had negative effect on the effectiveness of PAA in eliminating Salmonella populations, providing insight into the influence of TSS on disinfection processes. These findings have implications for water treatment facilities and highlight the significance of monitoring TSS levels to ensure effective disinfection using PAA.