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The late blowing in cheese: a new molecular approach based on PCR and DGGE to study the microbial ecology of the alteration process.

Authors
  • Cocolin, Luca
  • Innocente, Nadia
  • Biasutti, Marialuisa
  • Comi, Giuseppe
Type
Published Article
Journal
International Journal of Food Microbiology
Publisher
Elsevier
Publication Date
Jan 01, 2004
Volume
90
Issue
1
Pages
83–91
Identifiers
PMID: 14672833
Source
Medline
License
Unknown

Abstract

A molecular biology method based on polymerase chain reaction (PCR) and denaturing gradient gel electrophoresis (DGGE) was developed to detect Clostridium spp. in cheese samples suspected of late blowing. Strains of Clostridium spp. and different Lactic Acid Bacteria species, obtained from international collections, were used to determine the experimental conditions for the PCR amplification and DGGE differentiation. DNA extracted directly from cheeses with late blowing symptoms was subjected to PCR and DGGE analysis and traditional agar plating was performed for samples pasteurized and enriched overnight. Moreover, volatile fatty acids were determined for comparison purposes. The PCR-DGGE results were in agreement with the plating performed, and only samples presenting DGGE bands migrating at the same position as Clostridium spp. bands, showed the presence of Clostridium colonies on Reinforced Clostridial Medium plates. Butyric acid contents were high (>100 mg/kg) in the cases of positive DGGE results, underlining the suitability of the protocol for the study of cheese spoilage. The sensitivity of the method is estimated to be 10(4) CFU/g.

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