To better predict risk of Salmonella infection from chicken subjected to temperature abuse, a study was undertaken to develop a predictive model for survival and growth of Salmonella Typhimurium DT104 on chicken skin with native flora. For model development, chicken skin
portions (2.14 cm2) were inoculated with 0.85 log of Salmonella Typhimurium DT104 (ATCC 700408) and then stored at 5 to 50°C for 8 h. Kinetic data from the storage trials were fit to a primary model to determine lag time (λ), specific growth rate (μ), and the
95% prediction interval (PI). Secondary models for λ, μ, and PI as a function of storage temperature were developed and then combined with the primary model to create a tertiary model. Performance of the tertiary model was evaluated against dependent data, independent data for interpolation,
and independent data for extrapolation to kosher chicken skin by using an acceptable prediction zone from −1 (fail-safe) to 0.5 (fail-dangerous) log per skin portion. Survival of Salmonella Typhimurium DT104 on chicken skin was observed during 8 h of storage at 5 to 20°C and
at 50°C, whereas growth was observed from 25 to 45°C and was optimal at 40°C with a λ of 2.5 h and a μ of 1.1 log/h. Variation of pathogen growth, as assessed by PI, increased in a nonlinear manner as a function of temperature and was greater for growth conditions than
no-growth conditions. The percentage of acceptable prediction errors was 82.6% for dependent data, 83.7% for independent data for interpolation, and 81.6% for independent data for extrapolation to kosher skin, which all exceeded the performance criterion of 70% acceptable predictions. Thus,
it was concluded that the tertiary model provided valid predictions for survival and growth of Salmonella Typhimurium DT104 from a low initial dose on both nonkosher and kosher chicken skin with native flora.
Document Type: Research Article
U.S. Department of Agriculture, Agricultural Research Service, Microbial Food Safety Research Unit and USDA/1890, Center of Excellence in Poultry Food Safety Research, Room 2111, Center for Food Science and Technology, University of Maryland
Eastern Shore, Princess Anne, Maryland 21853, USA
Publication date: February 1, 2009
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