Bacillus species in raw milk and in the farm environment

Occurrence of aerobic and/or facultatively anaerobic sporeforming bacteria of the genus Bacillus was examined in raw milk (milk of individual cows, bulk tank milk) and in the environment of one farm (feed, faeces,swabs of teats,skin) during one year. The samples were collected monthly. The highest count of these bacteria was found in the majority of samples in the period from August to October as a result of change of the food ration and bad hygiene of the udder before milking. From 276 samples, 197 strains were isolated. 177 strains were classified as morphological group I, 4 strains as morphological group II and 10 strains as morphological group III. Six strains were not identified. B. licheniformis was the most commonly isolated species found in milk (in 85% of the raw milk samples) and farm environment.. The other species, including B. cereus, were found more or less frequently. Seasonal variations were not noticed.