Studies on occurrence and heat treatment of Listeria monocytogenes in milk and some dairy products [electronic resource].

Includes references.

A total of 210 random samples of 2 groups, the first group contain 120 samples of raw milk, water, animal feeds and animal feces (30 samples of each type) and second group contain 90 samples of sterilized milk, kareish cheese and yoghurt (30 samples of each type) were collected from some private farms in Sharkia Province, samples examined for the presence of Listeria species. Three Listeria spp. were isolated from raw milk, water, animal feeds, animal feces, sterilized milk, kareish cheese and yoghurt; L. monocytogenes was presented by 3.3%, 0%, 6.6%, 3.3%, 3.3%, 3.3% and 0% ; L. innocua was present by 3.3%, 0%, 10%, 10%, 0%, 3.3% and 0%; from raw milk, water, animal feeds, animal feces, sterilized milk, kareish cheese and yoghurt respectively and L. welshimeri was present by 0% from raw milk, water, animal feeds, animal feces, sterilized milk, kareish cheese and yoghurt respectively. The present investigation showed three trials on sterile milk which were inoculated with 4 x 108 CFU/ml of L. monocytogenes as an initial count to detect the thermal resistance of the organisms when exposed to boiling temperature (60°C) at different times(l-4 minutes).

Summary in Arabic.

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