Bacterial Inactivation by Common Food Industry Sanitizers

The efficacy of peracetic acid (0.05%, 0.5%, and 1%), sodium hypochlorite (0.2%, 0.6%, and 1%), and benzalkonium chloride (0.3%, 1.15%, and 2%) was evaluated against Staphylococcus aureus (ATCC 6538), Salmonella enterica serovar Typhimurium, (ATCC 14028), Enterococcus hirae (ATCC 8043), Pseudomonas aeruginosa (ATCC 9027), Escherichia coli (ATCC 9027), and Listeria monocytogenes (ATCC 35152) using stainless steel discs, following European Committee for Standardization (CEN) guidelines. According to CEN, a sanitizer must achieve at least a 5 Log10 CFU reduction to be considered effective. Peracetic acid at 1% demonstrated the highest inactivation capacity, reducing all tested strains by more than 7 Log10 CFU/mL. P. aeruginosa (ATCC 9027) showed high tolerance to sodium hypochlorite and benzalkonium chloride, with reductions below 2 Log10 CFU/mL even at maximum concentrations. Both sodium hypochlorite and benzalkonium chloride, at their highest tested concentrations, effectively inactivated S. aureus, S. typhimurium, E. hirae, L. monocytogenes, and E. coli, achieving reductions greater than 7 Log10 CFU/mL. Overall, sanitizers were effective only at intermediate or maximum concentrations recommended by the manufacturers, suggesting that minimum label concentrations should be avoided to ensure microbiological control.