Heat transfer models for predicting Salmonella enteritidis in shell eggs through supply chain distribution

Area of Science:

• Food Science
• Microbiology
• Mathematical Modeling

Background:

• * Egg and egg preparations are significant sources of Salmonella enteritidis infections.
• * Time-temperature dynamics are critical for controlling Salmonella enteritidis in commercial shell eggs.

Purpose of the Study:

• * To validate a computer-aided mathematical model for estimating shell egg temperatures under various storage conditions.
• * To assess the model's accuracy in predicting microbial population growth for food safety applications.

Main Methods:

• * A mathematical model incorporating egg geometry and composition was developed using finite difference and finite element numerical techniques.
• * Key thermal parameters (heat transfer coefficients, thermal conductivity, specific heat) were determined via inverse procedures using experimental temperature data.
• * Model-predicted temperatures were compared with experimental data and applied to a Salmonella enteritidis growth model to evaluate prediction errors.

Main Results:

• * The mathematical model accurately estimated shell egg surface and interior temperatures under variable ambient and refrigerated storage.
• * The model demonstrated low errors (1.1% for finite difference, 0.8% for finite element) in predicting microbial population growth when compared to experimental measurements.

Conclusions:

• * The validated mathematical model provides a reliable tool for estimating shell egg temperatures, essential for food safety risk assessments.
• * The model's accuracy in predicting microbial growth supports its utility in managing Salmonella enteritidis contamination risks in eggs.