生乳의 微生物學的 硏究

Bacteriological Studies on Raw Milk

Microbial population of raw milk samples collected at Taegu area were enumerated by standard plate counts (SPC) and coliform counts, and 320 strains of coliform were studied the drug resistance and distribution of R factors. Total viable cells were from 1,921,000 to 9,933,000 and coliforms wete from 36,000 to 666,000 per mililiter of raw milk. In July the raw milk has highest SPC’s 22,451,000/ml and In January it has lowest SPC’s 93,000/ml. About 43 per cent of coliform strains isolated from raw milk were resistant to tetracycline (TC), streptomycine (SM), chloramphenicol (CM), ampicillin (AP) and kanamycine, alone or in combination thereof. Among the multiple resistant strains, the most common pattern was double resistant to SM and TC (14.6%), and followed by SM and CM(8.0%), and SM and AP (7.3%). About 28% of resistant strains carried R factors which were transferable to the recipient by conjugation.