Water properties in cream cheeses with variations in pH, fat, and salt content and correlation to microbial survival

J Agric Food Chem. 2012 Feb 22;60(7):1635-44. doi: 10.1021/jf204371v. Epub 2012 Feb 9.

Abstract

Water mobility and distribution in cream cheeses with variations in fat (4, 15, and 26%), added salt (0, 0.625, and 1.25%), and pH (4.2, 4.7, and 5.2) were studied using (1)H NMR relaxometry. The cheese samples were inoculated with a mixture of Listeria innocua, Escherichia coli O157 and Staphylococcus aureus, and partial least-squares regression revealed that (1)H T(2) relaxation decay data were able to explain a large part of the variation in the survival of E. coli O157 (64-83%). However, the predictions of L. innocua and S. aureus survival were strongly dependent on the fat/water content of the samples. Consequently, the present results indicate that NMR relaxometry is a promising technique for predicting the survival of these bacteria; however, the characteristics of the sample matrix are substantial.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cheese / analysis*
  • Cheese / microbiology*
  • Colony Count, Microbial
  • Escherichia coli O157 / growth & development
  • Fats / analysis*
  • Food Microbiology*
  • Hydrogen-Ion Concentration
  • Listeria / growth & development
  • Magnetic Resonance Spectroscopy
  • Sodium Chloride / analysis*
  • Staphylococcus aureus / growth & development
  • Water / analysis*

Substances

  • Fats
  • Water
  • Sodium Chloride