EVALUATION OF MICROBIOLOGICAL SAFETY OF SHRIMP COOKED IN A MICROWAVE-OVEN

The effect of different microwave power levels (240, 400, 560, and 800 W) on the survival of Listeria monocytogenes in inoculated shrimp was investigated. Thermal inactivation rates (D-values) of L. monocytogen es were determined using constant temperature water baths to establish the heat resistance of L. monocytogenes in shrimp. Shrimp were inocul ated with approximately 5 x 10(5) CFU/g of a five-strain mixture of L. monocytogenes. One hundred grams of shrimp were cooked in the microwa ve oven at different power levels using cooking times predicted by a m athematical model as well as 20% longer times than those obtained from the model. No viable L. monocytogenes were detected in uninoculated s hrimp after microwave cooking, but at least one replication of inocula ted shrimp tested positive for the presence of Listeria. No viable L. monocytogenes were detected in shrimp cooked at 120% of predicted time s.