Inactivation of Listeria innocua in brined white cheese by a combination of nisin and heat

Murad A. Al-Holy, Anas Al-Nabulsi, Tareq M. Osaili, Mutamed M. Ayyash, Reyad R. Shaker

Research output: Contribution to journalArticlepeer-review

54 Citations (Scopus)

Abstract

The objective of this study was to investigate the effect of nisin alone and in combination with heat (63 °C/5 min) on the inactivation of Listeria innocua in white cheese. Nisin was added at different concentrations (500, 1000, and 1500 IU ml-1) to pasteurized milk before curd formation. The curd was soaked for 24 h in 10% solution of brine containing ca 106 CFU ml-1 of a cocktail mixture of three strains of L. innocua. Part of the nisin treated samples were heat treated at 63 °C/5 min. Total mesophilic count (TMC), L. innocua survivors and changes in the pH of white cheese were monitored each 2 d for a period of 12 d of storage at 4 or 10 °C. Nisin at 500 IU ml-1 did not diminish TMC in white cheese compared to the control. The combination of heat and nisin (1000 or 1500 IU ml-1) exhibited a bacteriostatic effect on TMC throughout the storage period at 4 or 10 °C. Nisin at 500 IU ml-1 had a marginal inhibitory activity against L. innocua. However, nisin at 1000 and 1500 IU ml-1l resulted in a more than 2 log10 reduction in L. innocua count and the effect was more prominent at 10 °C. In comparison, the combination of nisin (1000 or1500 IU ml-1) and heat treatment exhibited a synergistic inhibitory activity against L. innocua, where a complete elimination of the organism was accrued after 6 and 8 d of storage at 10 and 4 °C. Therefore, nisin and heat combination could be used as a prudent hurdle to preclude the growth of Listeria in white cheese, especially under the condition of abused refrigeration conditions.

Original languageEnglish
Pages (from-to)48-53
Number of pages6
JournalFood Control
Volume23
Issue number1
DOIs
Publication statusPublished - Jan 2012
Externally publishedYes

Keywords

  • Heat
  • Listeria innocua
  • Nisin
  • Synergy
  • White cheese

ASJC Scopus subject areas

  • Biotechnology
  • Food Science

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