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INFLUENCE OF FOOD ENVIRONMENT ON LISTERIA MONOCYTOGENES INFECTION IN THE GUINEA PIG MODEL
Author(s) -
PANG HOANJEN E.,
MATTHEWS KARL R.
Publication year - 2006
Publication title -
journal of food safety
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.427
H-Index - 43
eISSN - 1745-4565
pISSN - 0149-6085
DOI - 10.1111/j.1745-4565.2006.00051.x
Subject(s) - listeria monocytogenes , pathogen , infectivity , virulence , biology , food science , microbiology and biotechnology , food contaminant , immunology , bacteria , biochemistry , gene , virus , genetics
Listeria monocytogenes is a widespread foodborne pathogen associated with severe illness in humans. Food composition, processing, storage, distribution and handling conditions are all factors that may individually or collectively contribute to the virulence of a pathogen. Using the guinea pig as a human surrogate, we investigated the impact of carrier vehicle and improper food handling practices on the infectivity of L. monocytogenes. Chocolate milk was artificially contaminated with L. monocytogenes prior to exposure to improper handling conditions. Improper handling of chocolate milk included leaving the milk at an elevated temperature (37C) and then placing it in a refrigerator (4C). Guinea pigs were orally challenged with either 10 2 or 10 8 cfu of L. monocytogenes in 1 mL of nutrient broth or chocolate milk that had been exposed to improper handling conditions. A third group was challenged with L. monocytogenes suspended in water. On days 2 and 4, upon enrichment of organ samples, the presence of L. monocytogenes was detected in 27% of the animals receiving the low dose regardless of the carrier vehicle and improper handling conditions. Animals fed the high dose (10 8 cfu) of L. monocytogenes had similar populations of the pathogen in the spleen and liver, regardless of the carrier vehicle. These results are significant in that a low dose (10 2 cfu) could lead to listerial infection. Under the conditions tested in this study, the carrier vehicle and exposure of the pathogen to improper handling practices had no detectable effect on the establishment of listerial infection in the guinea pig model.