Evaluation of commercially available produce antimicrobial washes to improve the quality and microbial safety of fresh produce

Abstract

Despite ongoing efforts to mitigate foodborne pathogen contamination, outbreaks associated with the consumption of fresh produce persist. This research evaluated the efficacy of three sanitizers in reducing various microorganisms on the surfaces of fresh cucumbers, broccoli, and lettuce under retail crisping conditions. Specifically, this study examined the ability of peracetic acid (PAA; 80 mg/L), hypochlorous acid (FAC; 50 mg/L free available chlorine), and accelerated hydrogen peroxide (AHP; 500 mg/L) to reduce pathogens (0.79–2.41 log CFU/g) and natural microbiota, including aerobic bacteria (0.54–2.55 log CFU/g) and yeasts and molds (0.34–1.58 log CFU/g), when applied for 1 min at both 5 and 25 °C. Results showed that all antimicrobial washes significantly reduced pathogens at both temperatures (p < 0.05). Cucumbers treated with the washing solutions exhibited a greater reduction in E. coli O157:H7 (up to 3.72 log CFU/g), S. typhimurium (up to 2.07 log CFU/g), and aerobic bacteria (up to 2.55 log CFU/g) compared to broccoli and lettuce (p < 0.05). This study also investigated the sanitizers' ability to prevent cross-contamination during the retail crisping process of lettuce heads (contact time: 1.5, 3, and 5 min). PAA and FAC significantly reduced cross-contamination with E. coli O157:H7 and S. typhimurium after 3 min of immersion. PAA also significantly reduced L. monocytogenes cross-contamination in batch 2 after 3 min of contact time (p < 0.05). In contrast, immersion of lettuce heads in water alone (WTC) was ineffective at reducing foodborne pathogens and cross-contamination risks. Highlighting the significance of postharvest antimicrobial washes in reducing the contamination and cross-contamination of fresh produce with foodborne pathogens at the retail level.