Studies on the Thermoduric Bacteria in Raw Milk and Dairy Products Part I. Distribution of Thermoduric Bacteria in Raw Milk and City Milk

유제품중(乳製品中)의 내열성세균(耐熱性細菌)에 관한 연구 제1보 원유(原乳)와 시유중(市乳中)의 내열성세균(耐熱性細菌)의 분포(分布)

  • Choi, Byung-Kyu (Department of Animal Food Technology, College of Animal Husbandry, Kon Kuk University)
  • 최병규 (건국대학교 축산대학 축산가공학과)
  • Published : 1976.03.28

Abstract

1. Three hundred and thirty three strains of thermoduric bacteria from raw milk, H.T.S.T. sterilized milk and U.H.T. sterilized milk in the market were isolated after heat treatment at $65^{\circ}C$ for 30 minutes. 2. By microscopical and physiological examination, including the tests for proteolysis and lipolysis, the isolates were identified as 125 strains of Bacillus stearothermophilus, 69 strains as Bacillus coagulans, 57 strains as Bacillus subtilis, 76 strains as Bacillus cereus and 3 strains as Lactobacillus thermophilus. 3. The susceptibility of the selected thermoduric strains to heat, the vegetative cells of some strains in skim milk survived the heat treatment at $65^{\circ}C$ for 30 minutes or $85^{\circ}C$ for 20 minutes but not survived at $100^{\circ}C$ for 10 minutes.

Keywords