Survival of Escherichia coli O157:H7, Listeria monocytogenes and Salmonella enterica on work-in-process (WIP) fresh-cut red cabbage

Work-in-process (WIP) fresh-cut vegetables, such as cabbage, often stored temporarily at refrigerated temperatures before final mixing, represent a critical yet under-explored safety hazard. This study was performed to evaluate the fate of bacterial populations on WIP red cabbage, as affected by holding time, temperature, and sanitizer treatment. WIP red cabbage was inoculated with five-strain composites, each of Escherichia coli O157:H7 (EC), Listeria monocytogenes (LM), and Salmonella enterica (SE), followed by washing with 100 ppm free chlorine (pH 6.5), 80 ppm peracetic acid (PAA), or water, and storage at 4, 8, and 12 °C for seven days. Populations of inoculated pathogens, mesophilic bacteria, psychrotrophs, and yeast and mold were monitored on days 0, 1, 4, and 7. Quadratic response surface regression models were employed to predict pathogen growth and survival as functions of holding temperature and time. Results demonstrated that EC and SE did not grow at 4 and 8 °C but increased by up to 2.2 log CFU/g at 12 °C within seven days, with no significant (P > 0.05) differences among sanitizing treatments. In contrast, LM populations increased during seven days at 8 and 12 °C with significantly higher growth rates in PAA-treated samples (1.5 and 2.5 log, respectively) than those treated with chlorine-treated samples (0.7 and 1.3 log, respectively). Populations of psychrotrophic bacteria, and yeast and mold increased over time at all temperatures, but samples treated with PAA often resulted in significantly greater increases during storage. This study demonstrates that sanitizing washes, along with storage temperature and time, influence bacterial growth on WIP red cabbage.