The effects of storage conditions and the natural microbiome of nontraditional fresh-cut salad ingredients on the fate of Listeria monocytogenes

<p>Consumer demand for bagged salad has moved beyond shredded iceberg and chopped romaine to more nutritionally dense greens with bold flavors. New salad ingredients include beet greens, kale, Brussel sprouts, and broccoli stalk. Many of these ingredients have not normally been consumed raw or may not have even been widely consumed. The purpose of this project is to determine the fate of L. monocytogenes on non-traditional salad ingredients under ideal, abusive and "real-world" storage conditions and to understand the influence of the produce microbiome on L. monocytogenes behavior. Beet greens, kale, Brussel sprouts, and broccoli stalk will be inoculated with L. monocytogenes and incubated at 4, 12, 22 and 35°C. L. monocytogenes populations and the microbiome will be monitored over the incubation period. To further assess L. monocytogenes growth risk product will be tested under simulated storage and distribution conditions. This part of the study will be done with L. innocua after conducting a challenge study to confirm its acceptability as a surrogate. Then to assess the potential growth of L. innocua under simulated conditions, product inoculated with the surrogate will be subjected to physical and temperature abuse typically experienced during shipment from the distribution center to the retail outlet. Results from this project will provide the fresh-cut produce industry with knowledge on the growth or no growth of L. monocytogenes on non-traditional salad ingredients that can then be used to develop data-driven risk management practices.</p>