ABSTRACT
BACKGROUND: To assess current microbiological risks of raw cow's milk. The presented work reports the prevalence of selected bacteria on Czech dairy farms in 2010 and compares the results with a similar study in 2002. MATERIAL AND METHODS: The prevalence of bacteria was studied by culture methods using milk filters made from non-woven fabric collected from dairy farms throughout the year 2010. Together 260 filters from 65 dairy farms were tested. The prevalence of Campylobacter spp., Listeria monocytogenes, Staphylococcus aureus, Escherichia coli O 157 and Salmonella spp. in filters was tested. In staphylococci, genes encoding enterotoxin-production were studied. In Campylobacter spp., resistance to antibiotics was ascertained. RESULTS: In 2010, the prevalence rates of selected bacteria on farms were as follows: Campylobacter spp. 3%, Escherichia coli O 157 0.4%, Salmonella spp. 0.8%, Listeria monocytogenes 10% and Staphylococcus aureus 31%. In 12% of the tested filters, S. aureus with the genetic make-up for enterotoxin production was isolated. Antibiotic resistance in Campylobacter spp. isolated from dairy farms is different from that in human or poultry isolates. CONCLUSION: Raw cow's milk contains bacteria capable of causing human alimentary tract diseases. The above microbiological risks for consumers are eliminated by proper storage conditions (below 10 degrees C) and heat treatment (boiling) of raw milk.
