Graduate Studies
First Advisor
Byron D. Chaves
Date of this Version
8-2024
Document Type
Thesis
Citation
A thesis presented to the faculty of the Graduate College at the University of Nebraska in partial fulfillment of requirements for the degree of Master of Science
Major: Food Science and Technology
Under the Supervision of Professor Byron D. Chaves
Lincoln, Nebraska, August 2024
Abstract
Clostridium perfringens is considered a significant pathogen associated with processed meat and poultry products. Related diseases have been linked to improper cooling and hot holding, indicating the potential outgrowth during these processes. This study aims to develop a predictive microbiological model to forecast the growth rate of C. perfringens in cooked, uncured turkey sausages by adjusting intrinsic product factors, such as salt and sodium bicarbonate concentrations and estimate the growth of C. perfringens in turkey meat under 8 h dual-rate linear dynamic cooling conditions to determine its growth kinetics.
The experiment employed a strain isolated from turkey and a total of 24 treatments, comprising two replications, three sodium bicarbonate concentrations, and four salt concentrations. The treatments were cooled from 54.4 °C to 26.7 °C within two hours and then to 4.4 °C within six hours. To ensure consistency, the inoculum and each sample were prepared in advance. During the cooling process, microbial analysis was conducted on nine samples, and non-inoculated meat tested negative for Clostridium perfringens. In addition to bacterial enumeration, the pH value was characterized after cooking poultry products.
The goodness-of-fit indicator demonstrated that the developed primary and secondary models were fitted with a high degree of precision. The growth rates of different salt concentrations and pH demonstrated that the intrinsic factors of the products had a significant impact (p < 0.05) on the growth rate of Clostridium perfringens. Furthermore, the findings of this study corroborate those of the developed dynamic model, which indicates that temperature is the primary factor influencing the growth rate of C. perfringens. The well-fitted primary and secondary model offers valuable insights for the production of small-diameter products with varying salt concentrations and pH values.
Advisor: Byron D. Chaves
Comments
Copyright 2024, Mohan Li. Used by permission