Germicidal efficacy of sanitizers on food-borne bacteria and effect of sanitizes in CIP and SIP simulation

The germicidal efficacy of six sanitizers against food-borne bacteria and spores (Escherichia coli, Salmonella Typhimurium, Staphylococcus aureus, Pseudomonas aeruginosa, and Bacillus subtilis spores) and the effect of these sanitizers in simulation of cleaning and sterilizing in place were evaluated. The most effective sanitizer solution was peracetic acid (PAA), which was capable of reducing E. coli populations by more than 5 log CFU/g at 60 mg/L. The rest of the sanitizers resulted in a population reduction of less than 5 log CFU/g at 150 mg/L in phenol coefficient test. The effect of acid-anionic sanitizer (ABF) and PAA against E. coli and S. aureus was affected by both pH and temperature. The synergism of sanitizers on germicidal efficacy has also been examined in this study. It was observed that the combination of PAA and ABF presented high efficacy against spores of B. subtilis. 0.2 % PAA in combination with 0.1 % ABF reduced 7.6 log spores. The simulation of cleaning-in-place (CIP) and sterilization-in-place (SIP) revealed that most of organisms were eliminated during CIP. B. subtilis spores holding strong attachment and heat resistance could be eliminated with the combination of 0.2 % PAA and 0.1 % ABF. These findings showed that germicidal efficacy against bacteria and spores was affected by the type of sanitizer, concentration, and environmental conditions, which provides the guidelines in lowering the concentration of sanitizers through synergistic activity and further may be valuable references for sanitation to compete the cycle of good hygiene practices in a proper CIP/SIP process.