Understanding a food’s ability to support the growth and/or survival of a pathogen throughout the supply chain is essential to minimizing large-scale contamination events. The purpose of this study was to examine the behavior (growth and/or survival) of Listeria monocytogeneson broccoli and cauliflower florets stored under different post-harvest temperatures utilized along the supply chain. Broccoli and cauliflower samples were inoculated at approximately 3 log CFU/g and stored at temperatures: 23±2, 12±2, 4±2, and -18±2°C. Samples were enumerated at 0, 0.167 (4 h), 1, 2, 3, and 4 (23±2°C); 0, 0.167, 1, 2, 3, 4, 7, 10 and 14 (12±2°C); 0, 0.167, 1, 2, 3, 4, 7, 10, 14, 21 and 28 (4±2°C); and 0, 1, 7, 28, 56, 84, 112, 140 and 168 (-18±2°C) d. L. monocytogenes populations were determined from plating samples onto tryptic soy agar and modified Oxford agars supplemented with nalidixic acid. Broccoli and cauliflower supported the growth of L. monocytogenes at 23, 12, and 4°C, with higher growth rates observed at higher temperatures. Populations of L. monocytogenes on broccoli and cauliflower samples significantly increased within 1 d at 23°C (1.6 and 2.0 log CFU/g, respectively) (P ≤ 0.05). At 12°C, populations of L. monocytogenes on broccoli and cauliflower samples significantly increased over 14 d by 1.4 and 1.9 log CFU/g, respectively (P ≤ 0.05). No significant difference over time was observed in L. monocytogenes populations on broccoli and cauliflower samples held at refrigeration, until populations began to grow by d 10 for both commodities (P> 0.05). Under frozen storage (-18°C),populations of L. monocytogenes survived on broccoli and cauliflower at least up to 168 d. Broccoli and cauliflower may be stored at lower temperatures to minimize L. monocytogenes growth potential, as growth rates were lower at 4°C, compared to at 12 and 23°C.

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