The 2011 multistate listeriosis outbreak associated with whole cantaloupe has heightened concerns regarding commercial handling and preparation practices for melons. In response, two separate studies were conducted to: (1) assess the transfer of Listeria monocytogenes during cutting, slicing, dicing in melons and (2) measure growth during subsequent storage of cantaloupes. Initially, cantaloupe and honeydew melon rinds containing L. monocytogenes populations (J22F, J29H, and M3) of 6.1 and 4.4 log CFU/cm2, stored at 4 and 30oC were cut with a sterile cork borer through the blossom scar, stem scar, and circumference regions of the rind to evaluate the L. monocytogenes transfer to the edible melon flesh. L. monocytogenes transfer ranged from 1.2 to 4.0 and 0.2 to 1.8 log CFU/cm2 for cantaloupe and honeydew. Overall, no significant difference in L. monocytogenes transfer was seen at different depths or product temperatures (P > 0.05). L. monocytogenes transfer from one inoculated melon to subsequent uninoculated melons was evaluated after mechanical slicing (Vollrath Redco 401N) of the intact fruit and dicing (Nemco 55650 dicer) of the flesh. Diced cantaloupe samples were stored (4, 7, and 10oC for seven days) and microbiologically analyzed for growth and survival of L. monocytogenes. During slicing, L. monocytogenes was transferred to uninoculated cantaloupe and honeydew melons were statistically similar (P > 0.05), ranging from 0.1 to 1.5 and 0.1 to 0.5 log CFU/g, respectively. During the storage of diced cantaloupes, L. monocytogenes generation time was 0.74 days for 10oC, with minimal growth observed at 4 and 7oC.
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