Dissertation
Thermal Resistance and Survival of Salmonella in Chocolate Products As Influenced By Water Activity
Washington State University
Doctor of Philosophy (PhD), Washington State University
2023
DOI:
https://doi.org/10.7273/000005279
Abstract
Recently, Salmonella contamination in chocolate has been a primary concern in confectionery. There is a strong need for the chocolate industry to understand the survival of Salmonella during thermal treatment and storage. The objectives of this study were to: 1) Study the survival and thermal resistance of Salmonella during the storage at two different water activities (aw = 0.25 and 0.50); 2) Investigate the influence of temperatures (70, 75 80 ℃) and aw (0.23, 0.33, 0.43) on the thermal resistance of Salmonella in milk chocolate; and 3) understand the impact of aw (0.23, 0.33, 0.43) on the thermal resistance of Salmonella in different chocolate products.The study showed less than a 4-log reduction in chocolate products over 12 months at room temperature. The higher population of Salmonella was obtained at a lower aw level (aw = 0.25). The results also showed a linear relationship between logarithmic D-values of Salmonella and aw at different treatment temperatures. The D-value increased with lower treatment temperatures and the aw increased at elevated temperatures in different chocolate products. The D-value of Salmonella decreased with increasing aw in three chocolate samples.
In conclusion, the desiccated environment could enhance the survival of Salmonella during thermal treatments and storage. This research may help the industry design proper processing conditions such as moisture control, conching temperature, and time in chocolate processing. The outcome of this research contributes to microbial safety in chocolate products.
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Details
- Title
- Thermal Resistance and Survival of Salmonella in Chocolate Products As Influenced By Water Activity
- Creators
- Sicheng Sun
- Contributors
- Juming JT Tang (Advisor)Meijun MZ Zhu (Committee Member)Shyam S Sablani (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Biological Systems Engineering, Department of
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 136
- Identifiers
- 99901019835901842
- Language
- English
- Resource Type
- Dissertation