Print Email Facebook Twitter Studies on the risk assessment of Listeria monocytogenes Title Studies on the risk assessment of Listeria monocytogenes Author Notermans, S. Dufrenne, J. Teunis, P. Chackraborty, T. Centraal Instituut voor Voedingsonderzoek TNO Publication year 1998 Abstract Humans are frequently exposed to Listeria monocytogenes, and high numbers may be ingested during consumption of certain types of food. However, epidemiological investigations show that listeriosis is a rare disease. Risk assessment studies using an animal mouse model indicate that almost all L. monocytogenes serovars present in food have clear virulent properties. The intravenous dose causing infection in 50% (IV ID50) of mice not previously exposed to L. monocytogenes (nonprotected mice) was 1.8 log10 units. For mice previously exposed to L, monocytogenes (immunologically protected mice), the IV ID50 was 5.6 log10 units. The ID50 of orally exposed nonprotected mice amounted to 6.5 log10 units, and no significant effects of type of food (water/milk) and storage time at 5°C (milk) were observed. The oral ID50 of immunologically protected mice was >9.0 log10 units. Furthermore, there was approximately 1-2 log10 difference between the ID10 and the lethal dose causing death in 50% (LD50). The results show that both the intestinal barrier and the specific immune defense mechanism are highly effective in preventing infection of mice orally exposed to L. monocytogenes. Delaying the immune defense had no effect on the protective activity of the intestinal barrier, indicating that these protective mechanisms operate independently. The risk assessment results obtained in the mouse model support the epidemiological finding that listeriosis is a rare disease in humans, despite frequent exposure to the organism. Subject Nutritionanimalarticlecheeseclassificationcomparative studyculture mediumfemalegermfree animalhumanimmunizationLD 50Listeria monocytogeneslisteriosismeatmicrobiologymilkmousepathogenicityrisk assessmentsea foodserotypingvegetablevirulenceAnimalsCheeseCulture MediaFemaleFish ProductsHumansImmunizationLethal Dose 50Listeria InfectionsListeria monocytogenesMeat ProductsMiceMilkRisk AssessmentSerotypingSpecific Pathogen-Free OrganismsVegetablesVirulence To reference this document use: http://resolver.tudelft.nl/uuid:ddfad3f1-39d6-42e2-88a8-ae496f4eda7e TNO identifier 234356 ISSN 0362-028X Source Journal of Food Protection, 61 (2), 244-248 Document type article Files To receive the publication files, please send an e-mail request to TNO Library.