Mycobacterium avium subsp. paratuberculosis (MAP) is the etiologic agent of paratuberculosis, a disease with considerable economic impact, principally on dairy cattle herds. Animals with paratuberculosis shed viable MAP especially in their milk, faeces and semen. MAP may have a role in the development of Crohn's disease in humans via the consumption of contaminated milk and milk products. The current methods of milk pasteurization are not sufficient to kill all MAP cells present in milk and MAP has been cultured from raw or pasteurized milk and isolated from cheese. The purpose of the present study was to review the different methods used for detection of MAP in milk and milk products. We analyze the current methods for direct or non direct identification of MAP and culture and molecular biology methods that can be applied to milk and milk products.

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The prevalence of strains of Staphylococcus aureus, coagulase-negative (CN) staphylococci, Listeria monocytogenes, Escherichia coli, Enterococcus faecalis, E. faecium and Bacillus cereus, was investigated in 111 bulk milk samples. Staphylococcus aureus was isolated from 38 samples, CN staphylococci from 63 samples, E. coli from 49 samples, E. faecalis or E. faecium from 107 samples, and L. monocytogenes from two samples. Bacillus cereus was not found in any of the samples and three samples were free of any of the selected species. Sensitivity to the anti-microbial drugs amikacin, ampicillin, ampicillin + sulbactam, cephalothin (CLT), cephotaxime, clindamycin, chloramphenicol (CMP), co-trimoxazole, erythromycin (ERY), gentamicin, neomycin, norfloxacin, oxacillin, penicillin, streptomycin (STR), tetracycline (TTC) and vancomycin was tested using the standard dilution technique. Minimum inhibitory concentration (MIC) characteristics (MIC50, MIC90, MIC range) were determined for each microbial species. Resistance against one or more anti-microbial drugs was found in 93% of S. aureus, 40% of CN staphylococci, 73% of E. coli, 88% of E.faecalis, 55% of E.faecium, and one L. monocytogenes strain. Most of the strains, particularly enterococci, were resistant to STR, TTC, and ERY (MIC50 4 microg/ml). A high percentage of staphylococci were resistant to beta-lactam antibiotics. High resistance to CLT was found in 11 strains of E. coli (MIC 256 microg/ml) and strains resistant to CMP (MIC90 16 microg/ml) were detected. The highest numbers of resistance phenotypes were found in E. coil (16) and CN staphylococci (12). Eighteen identical resistance phenotypes were demonstrated in indicator bacteria (E. coli, E. faecalis, E. faecium) and pathogens (S. aureus, CN staphylococci) isolated from the same bulk milk sample. The obtained resistance data were matched against the herd owners' information on therapeutic use of the drugs. This confrontation could not explain the findings of strains resistant to ERY or CMP. Our findings are evidence of selection of resistant strains among not only pathogenic agents, but also among indicator bacteria which can become significant carriers of transmissible resistance genes.

The aim of this study was to assess the quality of raw cow's milk from an automatic milking system. Samples of milk (48) were analyzed chemically and microbiologically and the somatic cell count, freezing point and inhibitor residues were determined. For comparison purposes, milk analysis data from two farms using conventional machine milking and 2008 milk analysis report data for the Czech Republic were used. All physical and chemical characteristics of the study samples were within the established limits

ABSTRACT:The freezing point (FP) was established in 48 bulk tank samples of raw and 48 samples of pasteurized goat milk that were collected in the course of lactation. Alongside, non-fat solids (NFS) content was monitored. Milk freezing point measurements were carried out using the thermistor cryoscope method in compliance with the standard CTS 570538 (1998). The mean freezing point of raw milk was found to be in an interval of -0.5513 ± 0.0046°C, variation ranged from -0.5466°C to -0.5567°C, with higher values in the spring months and a drop at the end of lactation. FP corresponded to the NFS content. The average freezing point of goat milk heat-treated on the farm to the temperature of 72°C over a period of 20 s was -0.5488 ± 0.0046°C, pasteurisation brought an average increase in FP by 0.0025°C.