Growth modeling of Uropathogenic Escherichia coli in ground chicken meat

Extraintestinal Pathogenic Escherichia coli (ExPEC), including Uropathogenic E. coli (UPEC), are common contaminants in poultry meat, and are a major pathogen associated with inflammatory bowel disease, ulcerative colitis, sepsis, and urinary tract infections. The purpose of this study was to determine the growth potential of UPEC in ground chicken meat. A multi-isolate cocktail of UPEC was inoculated into ground chicken meat 103−4 log CFU/g and incubated at 4, 10, 15, 22, and 30 °C. The USDA Integrated Pathogen Modeling Program (IPMP) was used to conduct mathematical modeling and validation of UPEC growth using the Huang Primary Model and the Huang Square Root Secondary Model. No growth occurred at 4 °C, while the lag phases were ca. 23.6, 11.5, 5.2, and 0.36 h at 10, 15, 22, and 30 °C. According to the model, the Tmin, the minimum temperature for UPEC growth in ground chicken, was 5.1 °C. The growth rates (μmax, ln CFU/g h−1) were ca. 0.06, 0.27, 0.48, and 0.90. Approximately 83.9% of the residual errors are between ±0.5 log CFU/g, suggesting that the predictive models and the associated kinetic parameters are sufficiently accurate in predicting the growth of UPEC in ground chicken. These models have been validated and can be used in risk assessment of ExPEC in poultry meat.