Inactivation of spores of Bacillus cereus in cheese by high hydrostatic pressure with the addition of nisin or lysozyme

Research output: Contribution to journalArticleResearchpeer-review

101 Citations (Scopus)

Abstract

The objective of this work was to study high hydrostatic pressure (HHP) inactivation of spores of Bacillus cereus ATCC 9139 inoculated in model cheeses made of raw milk, together with the effects of the addition of nisin or lysozyme. The concentration of spores in model cheeses was approximately 6-log10 cfu/g of cheese. Cheeses were vacuum packed and stored at 8°C. All samples except controls were submitted to a germination cycle of 60 MPa at 30°C for 210 min, to a vegetative cells destruction cycle of 300 or 400 MPa at 30°C for 15 min, or to both treatments. Bacillus cereus counts were measured 24 h and 15 d after HHP treatment. The combination of both cycles improved the efficiency of the whole treatment. When the second pressure-cycle was of 400 MPa, the highest inactivation (2.4 ± 0.1-log10 cfu/g) was obtained with the presence of nisin (1.56 mg/L of milk), whereas lysozyme (22.4 mg/L of milk) did not increase sensitivity of the spores to HHP. For nisin (0.05 and 1.56 mg/L of milk), no significant differences were found between counts at 24 h and 15 d after treatment. Considering that mesophilic spore counts usually range from 2.6 to 3.0 log10 cfu/ml in raw milk, HHP at mild temperatures with the addition of nisin may be useful for improving safety and preservation of soft curd cheeses made from raw milk.
Original languageEnglish
Pages (from-to)3075-3081
JournalJournal of Dairy Science
Volume86
DOIs
Publication statusPublished - 1 Jan 2003

Keywords

  • Bacillus cereus
  • High pressure
  • Lysozyme
  • Nisin

Fingerprint

Dive into the research topics of 'Inactivation of spores of Bacillus cereus in cheese by high hydrostatic pressure with the addition of nisin or lysozyme'. Together they form a unique fingerprint.

Cite this