An official website of the United States government.
Evaluate whether L. monocytogenes grown on different ready-to-eat meat products (wieners, deli meats), or in tryptose soy broth, differ in their resistance to the inhibitory effects of simulated gastric fluid, and their resulting virulence following introduction into the g.i. tract of mice; compare virulence of acid-sensitive and acid-tolerant transposon mutants of L. monocytogenes grown on different ready-to-eat meat products. Study will be used for predictive modeling of risk assessment for ingestion of L. monocytogenes.
Strains of L. monocytogenes will be grown in packages of ready-to-eat meat products (wieners or deli meat), or in tryptic soy broth. Log-phase organisms grown under each condition will then be incubated in vitro with simulated gastric fluid for varying lengths of time, and at various
temperatures. These incubations will also be performed with L. monocytogenes incubated with simulated gastric fluid in the presence of various amounts of homogenized meat product, to determine whether the latter protects the organism against the effects of gastric fluid.