Occurrence and Behaviour of Pathogenic Microorganisms Especially Listeria Monocytogenes in Milk and Some Dairy Products

samples of raw cow ’s a nd goat I s milk, e nv Lr o nme n t-alpl es (obtained from Experimental farm of Univ. Wdl;leningen,e Netherlands), cheese (soft and semi-hard) were sub] ectedbacteriological examination.Listeria monocytogenes could be detected in 7.3,SO, 100 and 50% of samples of raw cow’s milk, cow’s~eces, silage, bedding and grass, respecti~ely.Lis teria deni trif icans (19.5% of isolates) wasfound most frequently, followed by Listeria monocytogenes111% ), Listeria seeligeri (6.1%) and Listeria ivanovii& Listeria welshimeri (3.6% of each).The level of contamination of listeria in cheese3.29 x 10 /q average.present in 8% and 4% of examined cows milk samples,Yersinia enterocoli tica and Yersinia pseudotuberculosisres~ectively. In bovine faeces samples, only Yersiniapseudotuberculosis was demonstrated (5.3% of samples).The detection of Yersinia pseudotuberculosis :4%)cow’s milk has never been previously reported by anyresearcher in the avit1..:lable U t e r a t u r e .•All cowts milk samples proved to be Campylobacterfree. However, Campylobacter jejuni was found in 7. 9% ofbovine faecal samples.