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Published on: August 9, 2011
Influence of strain and trisodium phosphate concentration on growth parameters of Listeria monocytogenes in vitro
R Capita1, C Alonso-Calleja, M C García-Fernández
1Department of Food Hygiene and Food Technology, Veterinary Faculty, University of León, Spain. dhtrcg@unileon.es
Aims:
The present study was conducted to determine the influence of strain and trisodium phosphate (TSP) concentration in the growth of Listeria monocytogenes in vitro.
Methods And Results:
Three strains (ATCC 11916, 64d, isolated from chicken meat, and M2-5b, a clinical animal isolate) were inoculated in broth with 0, 0.5, 1 and 1.5% (w/v) of TSP. The shortest lag phase and highest maximum rate of growth (mu) were obtained in the presence of 0.5% TSP. In contrast, the highest lag phase and lowest mu were obtained with 1.5% TSP. For each TSP concentration, significant differences (P < 0.05) in lag phase and mu of the three L. monocytogenes strains were observed.
Conclusion:
The behaviour of L. monocytogenes is significantly influenced by both the origin of the strain and the salt concentration.
Significance And Impact Of The Study:
Our results indicate the importance of choosing an adequate TSP concentration for the decontamination of foods, because low concentrations could favour the growth of L. monocytogenes.
Insights
Trisodium phosphate (TSP) concentration and Listeria monocytogenes strain origin significantly impact bacterial growth. Low TSP levels may inadvertently promote Listeria monocytogenes growth, highlighting the need for careful concentration selection in food decontamination.
Area of Science:
- Food microbiology
- Bacterial growth kinetics
- Food safety interventions
Background:
- Listeria monocytogenes is a significant foodborne pathogen.
- Trisodium phosphate (TSP) is used as a food decontamination agent.
- Understanding TSP's effect on L. monocytogenes is crucial for effective food safety.
Purpose of the Study:
- To investigate the influence of different trisodium phosphate (TSP) concentrations on Listeria monocytogenes growth.
- To assess the impact of L. monocytogenes strain origin on its response to TSP.
Main Methods:
- In vitro inoculation of three L. monocytogenes strains (ATCC 11916, chicken isolate 64d, animal isolate M2-5b) in broth.
- Exposure to varying TSP concentrations (0, 0.5, 1, and 1.5% w/v).
- Measurement of bacterial growth parameters: lag phase duration and maximum growth rate (mu).
Main Results:
- Optimal growth (shortest lag phase, highest mu) occurred at 0.5% TSP.
- Inhibition of growth (longest lag phase, lowest mu) was observed at 1.5% TSP.
- Significant strain-dependent differences in lag phase and mu were noted across all TSP concentrations (P < 0.05).
Conclusions:
- Both TSP concentration and the specific strain of L. monocytogenes significantly affect bacterial behavior.
- Inadequate TSP concentrations in food decontamination could potentially enhance L. monocytogenes proliferation.
- Careful selection of TSP concentration is essential to prevent unintended promotion of Listeria monocytogenes growth.
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