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Published on: February 1, 2014
Quantification of Listeria monocytogenes in fermented sausages by MPN-PCR method
Aims:
To combine the principles of most-probable-number (MPN) statistics and the conventional PCR technique to enumerate Listeria monocytogenes in fermented sausages.
Methods And Results:
A simple method to enumerate L. monocytogenes in fermented sausages was developed and compared with direct plating in Palcam agar. Species-specific MPN-PCR, but not direct plating, made the enumeration of L. monocytogenes possible in all assayed samples.
Conclusions:
MPN-PCR proved to be a rapid and reliable method for enumerating L. monocytogenes in fermented sausages, including low contaminated samples.
Significance And Impact Of The Study:
This MPN-PCR technique may facilitate the enumeration of L. monocytogenes for routine analyses in fermented sausages without excessive work.
Insights
A new method combines most-probable-number (MPN) statistics with PCR to accurately count Listeria monocytogenes in fermented sausages. This MPN-PCR technique offers a rapid and reliable solution for routine food safety analysis.
Area of Science:
- Food Microbiology
- Molecular Biology
- Statistical Methods
Background:
- Accurate enumeration of Listeria monocytogenes is crucial for fermented sausage safety.
- Conventional methods like direct plating can be limited in sensitivity and scope.
- There is a need for improved methods to detect low levels of contamination.
Purpose of the Study:
- To develop and validate a novel method for enumerating Listeria monocytogenes in fermented sausages.
- To combine most-probable-number (MPN) statistical principles with polymerase chain reaction (PCR) technology.
- To compare the efficacy of the new method against traditional direct plating techniques.
Main Methods:
- Development of a species-specific most-probable-number polymerase chain reaction (MPN-PCR) assay.
- Enumeration of Listeria monocytogenes in various fermented sausage samples.
- Comparative analysis with direct plating on Palcam agar.
Main Results:
- The developed MPN-PCR method successfully enumerated Listeria monocytogenes in all tested fermented sausage samples.
- Direct plating on Palcam agar failed to detect Listeria monocytogenes in some samples where MPN-PCR was successful.
- The MPN-PCR technique demonstrated superior sensitivity for detecting low levels of contamination.
Conclusions:
- MPN-PCR is a rapid, reliable, and sensitive method for enumerating Listeria monocytogenes in fermented sausages.
- This technique is particularly effective for samples with low bacterial contamination.
- The MPN-PCR assay simplifies routine food safety analyses for Listeria monocytogenes in fermented sausages.
