Efficacy of Peroxyacetic Acid and Other Sanitizers for Ensuring Produce Safety

Introduction: Incidences of foodborne outbreaks caused by consumption of contaminated fresh fruits and vegetables have increased in the recent past. Escherichia coli O157, Listeria monocytogenes and Salmonella spp. are pathogens frequently associated with produce related outbreaks. Contaminated fresh fruits and vegetables are matter of concern, as they are often consumed raw, thus posing as a threat to human health. Therefore, disinfection of produce with an effective sanitizer is one of the critical steps in ensuring produce safety.

Purpose: The objective of this study was to evaluate the efficacy of chlorine-based sanitizer (acidic electrolyzed water, near neutral electrolyzed water (NNEO) and bleach), lactic acid, VigorOx^® 15 F&V (peracetic acid-based sanitizer), and DI water on produce inoculated with E. coli O157, L. monocytogenes and Salmonella Typhimurium DT104.

Methods: A five-strain cocktails of E. coli O157, L. monocytogenes, and Salmonella Typhimurium DT104 (each pathogen prepared separately) were used for surface inoculating produce (E. coli O157: romaine lettuce, lemons, tomatoes, and blueberries; L. monocytogenes: romaine lettuce and cantaloupe; Salmonella Typhimurium DT104: lemons, tomatoes, cantaloupe, and blueberries). Chlorine-based sanitizers at 100 ppm, VigorOx® 15 F&V at 45, 85, 100 ppm, lactic acid at 2% and DI water as control were used for washing inoculated produce with an automated produce washer for five minutes.

Results: All sanitizers showed a higher efficacy (2.8 to 6.8 log CFU) on produce samples with smoother texture (e.g., lemon, tomato, blueberry). Lower effectiveness (0.2 to 4.4 log CFU) was observed for produce with course surface (e.g., lettuce, cantaloupe). NNEO and VigorOx^® 15 F&V at 100 ppm were most effective (2.2-log CFU/g reduction) on lettuce inoculated with E. coli O157. Whereas, VigorOx^® 15 F&V at 100 ppm showed significantly (P<0.05) better results (4.4-log reductions) on cantaloupe inoculated with L. monocytogenes.

Significance: VigorOx® 15 F&V was found to be either superior or equally effective as chlorine-based sanitizers.