Recovery of Heat-Stressed Listeria monocytogenes from Experimentally and Naturally Contaminated Shrimp.

A method was developed to enhance recovery of thermally stressed Listeria monocytogenes from internally contaminated shrimp. Shrimp tail meat was inoculated with 105 L. monocytogenes cells/g and boiled for 1-5 min. Thermally stressed L. monocytogenes cells were recovered following cold enrichment for 3 d without broth. Methods of the Food and Drug Administration and the U.S. Department of Agriculture for isolating L. monocytogenes permitted recovery of the organism from shrimp boiled for 1 min: however, with the new method, L. monocytogenes cells were recovered from shrimp boiled up to 5 min. No Listeria spp. were recovered from naturally contaminated, frozen, imported shrimp after 1 min of boiling.