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item Oscar, Thomas

Submitted to: International Association for Food Protection Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 1/8/2006
Publication Date: 8/13/2006
Citation: Oscar, T.P. 2006. Predictive model for growth of salmonella typhimurium dt104 on ground chicken breast meat. International Association for Food Protection Proceedings. T4-04. pg. 83.

Interpretive Summary:

Technical Abstract: A multiple antibiotic resistant strain of Salmonella Typhimurium definitive phage type 104 (DT104) was used to investigate and model growth from a low initial density (0.6 log/g) on ground chicken breast meat portions (1-g). Most probable number and viable counts on a selective medium with four antibiotics enumerated the pathogen over a wide range of temperature (10 to 40C). Data from five replicate challenge studies per temperature were combined and fit to a primary model to determine maximum specific growth rate (SGR), maximum population density (MPD) and the 95% prediction interval (PI). Non-linear regression was used to obtain secondary models as a function of temperature for SGR, MPD and PI, which ranged from 0.048 to 0.41/h, 1.6 to 9.4 log/g and 1.4 to 2.4 log/g, respectively. Secondary models were combined with the primary model in a computer spreadsheet to create a tertiary model for predicting the variation (95% PI) of pathogen growth among portions of ground chicken breast meat. The criterion for acceptable model performance was that 90% of observed values for pathogen density (PD) at a given time had to be within the 95% PIs predicted by the tertiary model. For data (n = 236) not used in model development but collected using the same methods, 94% of observed PD values were in the predicted 95% PIs of the tertiary model. Thus, the tertiary model was successfully validated for predicting the variation of growth of S. Typhimurium DT104 among portions of ground chicken breast meat and from a low initial density.