15D-2 |
A predictive model for the cross-contamination of Campylobacter jejuni and Salmonella typhimurium during poultry chilling process |
H. YANG1, Y. Li1, and M. G. Johnson2. (1) Dept. of Biological & Agricultural Engineering, Univ. of Arkansas, Fayetteville, AR 72701, (2) Dept. of Food Science, Univ. of Arkansas, Fayetteville, AR 72701 The cross-contamination of Campylobacter jejuni and Salmonella typhimurium in a poultry chiller presents a challenge to the poultry industry for the food safety of poultry product. The purpose of this research was to develop a microbial model as the function of the initial contamination ratio, the chlorine level in chilling water and the water age to predict the cross-contamination of C. jejuni and S. typhimurium during poultry chilling. For each treatment thirty chicken drumsticks were chilled in a chiller simulator for 50 min with 4 L of chilling water, 240 L/h of overflowing water and 50 L/h of air for agitation. Chilling temperature was controlled at 2-4°C. Before chilling, some chicken drumsticks were inoculated with C. jejuni or S. typhimurium to obtain different initial contamination ratios (3.3, 23.3 and 43.3%). Variable chilling conditions were chlorine level (0 and 50 ppm) and water age (0 and 10 h). After the chilling the positive/negative contamination was determined for each drumstick using microbial plating method. Based on the experimental data a model was determined using the statistical software JMP IN. A probability model, p=1/(1+e-y), was developed, where P is the contamination probability of C. jejuni or S. typhimurium during poultry chilling, y is a linear function of the variable factors, initial contamination ratio, chlorine level and the water age. The Hosmer and Lemeshow statistic for determined model, XHW (22.07), was smaller than the chi-square distribution of X20.05,30 (43.77), indicating a good fit between the data and the model. The model predicts that in the 8-h chilling water with 50 ppm of chlorine, chicken drumsticks with 43% of the initial contamination ratio have the cross-contamination probability of 0.07 for S. typhimurium and 0.02 for C. jejuni, respectively. This model may assist poultry processors in controlling microbial cross-contamination during poultry chilling.
Session 15D, Food Engineering: Processing Technologies
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