Growth behavior of low populations of Listeria monocytogenes on fresh-cut mango, melon and papaya under different storage temperatures.

ABSTRACT

The growth behavior of Listeria monocytogenes low population (1-4 cells/sample) on fresh-cut mango, melon, papaya and fruit mix stored at 4, 8, 12 and 16 °C was evaluated over 10 days. Mango showed the lowest counts for L. monocytogenes during 10 days regardless of storage temperature (<1.7 log cfu.g-1). Melon supported high bacterial growth over 10 days, reaching 5 log cfu.g-1 at 16 °C. Both the fruit and storage temperature influenced the Listeria low population growth potential (δ). Cumulative frequency distribution of L. monocytogenes showed that after 10 days, 100% of fresh-cut fruits and fruit mix stored at 4 °C remained ≤2 log cfu.g-1, while at 12 and 16 °C 100% of melon, papaya and fruit mix samples exceeded this limit. At 8 °C, 100% of mango and fruit mix samples remained below this limit after 10 days, whereas 100% of melon and papaya reached it after 7 days. Results indicate 4 °C as the ideal to store safely fresh-cut mango, melon, papaya and fruit mix for 10 days. Besides, 8 °C can also be an option, but not for melon and papaya. Findings highlight the ability of L. monocytogenes to survive and grow in fresh-cut fruits even at a very low initial population levels.