MICROBIOLOGICAL QUALITY OF COWS' MILK IN ORGANIC FARMING (PRELIMINARY REPORT)

The objective of the present study was to investigate the microbiological content of cows' milk in Latvia's organic farms with a purpose to detect potential microbiological threats in milk. Samples were collected in December 2011 at 12 biological dairy farms of Latvia. Raw milk samples (N= 155) obtained from cow composite milk were studied. The total mesophilic aerobic and facultative anaerobic microorganisms (MAFAM), the presence of coliforms and coagulase-positive staphylococci, count of yeasts and moulds were analysed using standard methods. Of the sampled cows 50% had a low somatic cell count (SCC) (< 200,000 cells mL(-1)), 23% -high, but 27% had a very high SCC (> 500,000 cells mL(-1)). The mean value of MAFAM in the samples with low, high and very high SCC was 4.7, 5.0 and 5.0 log10 colony forming units (cfu) mL(-1), respectively. The yeasts were present in 57% of milk samples with the mean concentration of 3.1 log10 cfu mL(-1). Moulds were found in 27% of all milk samples; their mean concentration was 4.4 log10 cfu mL(-1). Identified mould strains belonged to genera Absidia, Aspergillus, Geotrichum, Mucor and Penicillium. In cases of subclinical mastitis and latent mammary infection the most distributed mastitis pathogens were Staphylococcus aureus, Micrococcus kristinae, Bacillus cereus and coagulase negative staphylococci.