Heat resistance of salmonellae in concentrated milk

Appl Microbiol. 1972 Feb;23(2):415-20.

Abstract

The heat resistance of Escherichia coli, Salmonella typhimurium, and Salmonella alachua in milk solutions containing 10, 30, 42, and 51% (w/w) skim milk for total solids was determined. Increased milk-solids level effected a significant increase in the heat resistance of each organism. Although E. coli was more heat-resistant than both strains of Salmonella in 10% milk, the situation was reversed in 42 and 51% milk. Prior growth temperature was found to exert a profound effect on the heat resistance of S. typhimurium. Growth of S. typhimurium in 42% milk solids for 24 hr did not greatly enhance the thermal resistance of the organism when heated in a fresh 42% solids concentrate. Application of a partial vaccum during heating greatly diminished the decimal reduction times of S. typhimurium and E. coli and, in addition, virtually eliminated the protective effect of increased solids level.

MeSH terms

  • Animals
  • Atmospheric Pressure
  • Bacteriological Techniques
  • Cell Count
  • Cell Survival
  • Escherichia coli / growth & development
  • Escherichia coli / isolation & purification
  • Food Microbiology*
  • Food Preservation
  • Hot Temperature*
  • Milk*
  • Salmonella / growth & development*
  • Salmonella / isolation & purification
  • Salmonella typhimurium / growth & development
  • Salmonella typhimurium / isolation & purification