Deterministic Approach and Monte Carlo Simulation to Predict Listeria monocytogenes Time to Grow on Refrigerated Ham:...

Area of Science:

• Food Microbiology
• Food Safety Science
• Microbial Growth Kinetics

Background:

• Consumer protection against foodborne illness is paramount.
• Ready-to-eat (RTE) foods like ham require careful storage to prevent pathogen growth.
• Understanding Listeria monocytogenes behavior in RTE ham under domestic storage conditions is crucial for policy development.

Purpose of the Study:

• To assess Listeria monocytogenes growth in RTE ham under simulated domestic storage.
• To provide data supporting the development of effective food safety policies.
• To evaluate the impact of different temperature conditions on pathogen growth and shelf-life.

Main Methods:

• Artificially contaminated RTE ham (medium and high levels) was stored under isothermal (4°C, 5°C, 7°C) and dynamic (temperature fluctuations, intermittent room temperature exposure) conditions.
• The Baranyi and Roberts model was used to determine kinetic growth parameters.
• Sanitary risk time calculations and Monte Carlo simulations were employed to assess safety margins.

Main Results:

• Increased storage temperature significantly enhanced L. monocytogenes growth under isothermal conditions (p < 0.05).
• Storage at 4°C extended the safe consumption period for RTE ham by approximately 40-52% compared to 5°C and 7°C at medium contamination levels.
• Temperature fluctuations and intermittent exposure to ambient temperatures (25°C) substantially reduced safety margins, especially at low pathogen levels.

Conclusions:

• Storage temperature is a critical factor influencing L. monocytogenes growth in RTE ham.
• Simulated domestic storage conditions, including temperature fluctuations, pose a significant risk and shorten the safety margins.
• Stochastic modeling is valuable for predicting pathogen behavior under dynamic and fluctuating temperature scenarios in RTE foods.