Development of a steam treatment to eliminate Listeria monocytogenes from king Salmon (Oncorhynchus tshawytscha)

Abstract

A pilot plant steam treatment system was developed to reduce L. monocytogenes contamination on exterior surfaces of King Salmon (Oncorhynchus tshawytscha) prior to processing. Numbers of surviving L. monocytogenes cells on the surface were determined using an enrichment-based Most Probable Number (MPN) technique. Inoculated L. monocytogenes cells were not recovered from the surface of salmon after exposure to the steam treatment for 8 sec. A 4-log reduction in L. monocytogenes numbers was obtained. Treated salmon could be processed into a high-yielding, high-quality cold smoked product. An in-plant system was subsequently shown to reduce "naturally" occurring L. monocytogenes numbers and pro..