The antimicrobial interventions of cilantro (Coriandrum sativum) in mitigating cross-contamination of foodborne pathogens during the retail soaking process

The efficacy of commercially available antimicrobials for fresh produce, electrolyzed water (EW; ca. 60 mg/L of free chlorine), a combination of lactic acid and phosphoric acid-based (LPA), and citric acid-based (CA) was compared with tap water (TW) in preventing cross-contamination during the soaking step of crisping at a retail setting. A bunch of cilantro (103.7 ± 14.9 g/bunch) was inoculated with 3-strain cocktail of nalidixic acid-resistant Salmonella enterica and E. coli O157:H7, S. enterica and Listeria monocytogenes, or E. coli O157:H7 and L. monocytogenes (ca. 5.0 log CFU/g). One inoculated and seven non-inoculated cilantro bunches were soaked in 76 L of TW, EW, LPA, and CA for five minutes. Two additional soakings, each with eight bunches of non-inoculated cilantro were performed in the same soaking water. To determine the cross-contamination of inoculated foodborne pathogens via soaking water, the cilantro samples and soaking water following each soaking step were subjected to microbiological analyses using selective media supplemented with nalidixic acid (100 μg/mL). During the first soaking, significantly greater reductions in Salmonella (2.9 ± 0.5 log CFU/g), E. coli O157:H7 (3.0 ± 0.1), and L. monocytogenes (2.7 ± 0.3) on cilantro were achieved with EW compared to soaking with TW, LPA, and CA (P < 0.05). Cross-contamination of foodborne pathogens from inoculated cilantro to non-inoculated cilantro was completely mitigated by EW during three subsequent soaking events. With the exception of TW soaking water, no inoculated foodborne pathogens were detected in the 100 mL soaking water of EW, CA, and LPA collected. Including an appropriate concentration of chemical antimicrobial in water during the soaking step of crisping aids in mitigating cross-contamination of foodborne pathogen(s) in cilantro bunches.