P1-59 Development and Validation of a Heat and Mass Transfer Model for Air Cooling of Poultry Carcasses

Monday, July 29, 2013
Exhibit Hall (Charlotte Convention Center)
Jihan Cepeda, University of Nebraska-Lincoln, Lincoln, NE
Jeyamkondan Subbiah, University of Nebraska-Lincoln, Lincoln, NE
Harshavardhan Thippareddi, University of Nebraska-Lincoln, Lincoln, NE
Introduction: Rapid cooling immediately after slaughter and during storage are critical factors to assure microbial safety of poultry carcasses.  Computer models for simulating cooling of poultry carcasses are valuable tools to develop safe cooling procedures.  However, current models make simplifications that limit applicability for industrial use and are not available to poultry processors.

Purpose: Develop an accurate heat and mass transfer model for predicting carcass temperature during air cooling of poultry carcasses.

Methods: The coupled heat and mass transfer model considered heat conduction, convection, radiation, and moisture evaporation.  Three-dimensional geometries of poultry carcasses were generated from computer tomography images obtained from multiple carcasses.  The effect of non-uniform carcass composition and non-uniform thermal properties corresponding to the meat and bone sections of the carcasses was considered.  The model was developed using a combination of computer aided engineering software (e.g., COMSOL Multiphysics® and Materialise Mimics) and custom-made computer algorithms.  Model validation was conducted under laboratory and industrial settings, following normal processing conditions.

Results: The developed model was in agreement with experimental data.  Comparisons between the predicted and observed temperatures resulted in an RMSE of 2.3±1.5 °C, and a 0.08±0.05 log CFU/g deviation in the predicted net growth of Salmonella spp.  The model was successfully adapted to provide accurate predictions using input parameters such as air relative humidity, air velocity, cooler set-point temperature, and carcass weight. 

Significance: The developed model can be easily accessed and integrated with predictive microbial models through the food safety website: numodels4safety.unl.edu.  It can be used to support hazard analysis, development of critical limits, estimation of potential impact of cooling deviations, and simulation of multiple processing scenarios for quantitative microbial risk assessment.