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Development of listeria monocytogenes in monoxenic and polyxenic beef minces
Abstract:
The objective of this study was to determine the multiplication possibilities of Listeria monocytogenes in beef minces with a defined microflora (gnotoxenic). Selective counts were made for each species and each bacterial association for a period of 17 days after inoculation of the axenic meat. The concentration of L. monocytogenes did not increase, but remained constant in monoxenic meats. Associated with Lactobacillus plantarum, the number of Listeria tended to decrease. Conversely, in association with P. fluorescens, L. monocytogenes definitely multiplied, especially in polyxenic meats, the microflora of which is similar to that of conventional meats. Consequently, it seems that meat might constitute a source of L. monocytogenes infection.
Insights
Listeria monocytogenes multiplication in beef mince depends on associated bacteria. Pseudomonas fluorescens promoted growth, while Lactobacillus plantarum inhibited it, suggesting meat can be a source of Listeria infection.
Area of Science:
- Food Microbiology
- Bacterial Pathogenesis
- Food Safety
Background:
- Listeria monocytogenes is a significant foodborne pathogen.
- Understanding its behavior in meat is crucial for public health.
- Beef mince represents a common vehicle for pathogen transmission.
Purpose of the Study:
- To investigate the growth potential of Listeria monocytogenes in beef mince.
- To assess the influence of specific bacterial associations on Listeria monocytogenes proliferation.
- To determine if meat can serve as a reservoir for Listeria monocytogenes.
Main Methods:
- Gnotoxenic beef mince models were inoculated with Listeria monocytogenes.
- Selective bacterial counts were performed over 17 days.
- Listeria monocytogenes was studied in axenic, monoxenic (with Lactobacillus plantarum or Pseudomonas fluorescens), and polyxenic conditions.
Main Results:
- Listeria monocytogenes concentration remained constant in axenic meat.
- Listeria monocytogenes showed a tendency to decrease when associated with Lactobacillus plantarum.
- Significant multiplication of Listeria monocytogenes occurred in the presence of Pseudomonas fluorescens, particularly in polyxenic meat.
Conclusions:
- Bacterial interactions significantly impact Listeria monocytogenes survival and growth in beef mince.
- Pseudomonas fluorescens can enhance Listeria monocytogenes proliferation in meat.
- Meat products may act as a potential source for Listeria monocytogenes infections due to these interactions.