An alternative real-time PCR method to detect the Bacillus cereus group in naturally contaminated food gelatine: a comparison study

Lett Appl Microbiol. 2009 Jan;48(1):97-104. doi: 10.1111/j.1472-765X.2008.02495.x. Epub 2008 Nov 14.


Aims: Comparison of an internally controlled real-time PCR assay with the standard plate-based assay (ISO 21871) for the detection of Bacillus cereus group cells in gelatine.

Methods and results: A comprehensive TaqMan probe was designed allowing the real-time PCR assay to be fully inclusive and exclusive. An internal amplification control was designed and implemented at 500 copies per reaction without impact on target detection. Specific and selective detection of target cells was achieved with a quick and simple DNA preparation procedure. No significant difference (kappa = 0.99) was observed between the performance of the real-time PCR and the standard plate-based method on naturally contaminated gelatines (n = 197). Relative accuracy, relative sensitivity and relative specificity were > or =99%.

Conclusions: The real-time PCR assay is a valid alternative of the standard plate-based assay.

Significance and impact of the study: The real-time PCR assay decreased the time between sample collection and result from 2 days to 2 h, while analysis cost did not increase. The gelatine-producing industry can ensure gelatine safety and quality in a much faster way.

Publication types

  • Comparative Study
  • Evaluation Study

MeSH terms

  • Bacillus cereus / isolation & purification*
  • Food Microbiology*
  • Gelatin*
  • Oligonucleotide Probes / genetics
  • Polymerase Chain Reaction / methods*
  • Polymerase Chain Reaction / standards
  • Reference Standards
  • Sensitivity and Specificity


  • Oligonucleotide Probes
  • Gelatin