Combined Effects of pH, Nisin, and Temperature on Growth and Survival of Psychrotrophic Bacillus cereus
Authors: Jaquette, C. B.; Beuchat, L. R.
Source: Journal of Food Protection®, Number 5, May 1998, pp. 513-648 , pp. 563-570(8)
Abstract:Growth of vegetative cells and outgrowth of spores of enterotoxigenic psychrotrophic Bacillus cereus in refrigerated minimally processed food products is a public health concern. A study was undertaken to determine the combined effects of pH, nisin, and temperature on growth and survival of 20 strains of B. cereus. The minimum growth temperatures in tryptic soy broth (pH 7.3) and brain heart infusion broth (BHI broth, pH 7.4) were 5°C for two strains and 8°C for five other strains. Vegetative cells of four of eight strains grew at 8°C in BHI broth (pH 6.01 and 6.57) containing 10 μg of nisin per ml. At 15°C, all strains grew at pH 5.53 to 6.57; three strains tolerated nisin at 50 μg/ml (pH 6.57), whereas two other strains had a maximum tolerance of 10 μg of nisin per ml. Tolerance of vegetative cells of B. cereus to nisin increased as the pH of the broth was increased from 5.53 to 6.01 and again to pH 6.57. Outgrowth of spores (six of six strains tested) was inhibited by 5 and 50 μg of nisin per ml at 8 and 15°C, respectively. At 15°C, outgrowth of spores of two strains occurred at pH 6.52 in BHI broth containing 10 μg of nisin per ml. The effectiveness of nisin in controlling the growth of psychrotrophic strains of B. cereus capable of causing human illness was more pronounced at 8°C than at 15°C and as the pH was decreased from 6.57 to 5.53. Studies to determine the effectiveness of nisin in controlling growth of psychrotrophic B. cereus in nonpasteurized foods held at refrigeration temperatures are warranted.
Document Type: Research Article
Affiliations: Center for Food Safety and Quality Enhancement, University of Georgia, Griffin, Georgia 30223-1797, USA
Publication date: May 1, 1998
- IAFP members must first sign in on the right to access full text articles of JFP First published in 1937, the Journal of Food Protection®, is a refereed monthly publication. Each issue contains scientific research and authoritative review articles reporting on a variety of topics in food science pertaining to food safety and quality. The Journal is internationally recognized as the leading publication in the field of food microbiology with a readership exceeding 11,000 scientists from 70 countries. The Journal of Food Protection® is indexed in Index Medicus, Current Contents, BIOSIS, PubMed, Medline, and many others.
Print and online subscriptions are available to Members and Institutional subscribers. Online visitors who are not IAFP Members or journal subscribers will be charged on a pay-per-view basis. Information can be obtained by calling +1 800.369.6337; +1 515.276.3344; fax: +1 515.276.8655, E-mail: email@example.com or Web site: www.foodprotection.org
- Information for Authors
- Submit a Paper
- Subscribe to this Title
- Membership Information
- Information for Advertisers
- ingentaconnect is not responsible for the content or availability of external websites