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Detection of Live Escherichia coli O157:H7 Cells by PMA-qPCR
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Rapid and quantitative detection of viable emetic Bacillus cereus by PMA-qPCR assay in milk

Ping Zhou1, Guoyang Xie1, Taobo Liang1

  • 1State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, 330047, PR China.

Molecular and Cellular Probes
|August 20, 2019
PubMed

Insights

Detecting viable emetic Bacillus cereus in milk is crucial for food safety. A new propidium monoazide quantitative polymerase chain reaction (PMA-qPCR) method offers sensitive and selective detection of live emetic bacteria, minimizing food poisoning risks.

Area of Science:

  • Food Microbiology
  • Molecular Biology
  • Food Safety

Background:

  • Emetic Bacillus cereus causes vomiting-type food poisoning.
  • Accurate detection of viable bacteria is essential for food safety.
  • Existing methods may not reliably distinguish between live and dead bacterial cells.

Purpose of the Study:

  • To develop and optimize a propidium monoazide quantitative polymerase chain reaction (PMA-qPCR) assay.
  • To detect viable emetic Bacillus cereus in milk.
  • To ensure the assay is sensitive and selective.

Main Methods:

  • Optimization of propidium monoazide (PMA) concentration at 3 μg/mL.
  • Utilizing the cereulide synthetase gene (cesB) for primer selection.
  • Validation of the PMA-qPCR assay in pure culture and spiked milk samples.

Main Results:

  • The optimized PMA-qPCR assay demonstrated a limit of detection (LOD) of 10^2 CFU/mL.
  • The assay showed high selectivity, unaffected by non-target bacteria like E. coli O157:H7.
  • The method effectively inhibited PCR amplification from dead cells.

Conclusions:

  • The developed PMA-qPCR assay is a sensitive and selective tool for detecting viable emetic Bacillus cereus in milk.
  • This method has significant potential for enhancing food safety monitoring.
  • It aids in minimizing the risk of foodborne illnesses associated with emetic B. cereus.
Keywords:
Emetic Bacillus cereusLimit of detectionPropidium monoazideQuantitative PCR

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