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item Oscar, Thomas

Submitted to: International Association for Food Protection Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 2/21/2007
Publication Date: 7/8/2007
Citation: Oscar, T.P. 2007. Predictive model for growth of salmonella typhimurium dt104 on chicken frankfurters. Abstract. International Association for Food Protection Proceedings. P2-69.

Interpretive Summary:

Technical Abstract: Growth of Salmonella Typhimurium definitive phage type 104 (DT104) on portions (1-g) of chicken frankfurters from 0.4 to 3.3 log/g was investigated and modeled. A 3 x 4 most probable number assay that used a selective medium with four antibiotics enumerated the pathogen over a wide range of temperature (10 to 34C). Data from four replicate challenge studies per temperature were combined and fit to a primary model to determine maximum specific growth rate (SGR) and the 95% prediction interval (PI). Non-linear regression was used to obtain secondary models as a function of temperature for SGR and PI, which ranged from 0 to 0.16/h and 0.7 to 2.8 log/g, respectively. The pathogen did not grow on chicken frankfurter portions at 10 to 12C and showed only minor and slow growth at 14C. Secondary models for SGR and PI 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 chicken frankfurters. The criterion used for acceptable performance was that 90% of observed values for pathogen density (PD) at a given time had to fall in the 95% PIs predicted by the tertiary model. For data (n = 143) not used in model development but collected using the same methods, 92% of observed PD values were in the predicted 95% PIs of the tertiary model. Thus, the tertiary model was validated for predicting the variation of growth of S. Typhimurium DT104 among portions of chicken frankfurters.