Degree

Doctor of Philosophy (PhD)

Department

School of Nutrition and Food Sciences

Document Type

Dissertation

Abstract

The project's overall goal was to develop a computational multiphysics model to predict temperature and to validate the model in ready-to-cook shrimp in a microwavable package. Microwavable ready-to-cook meals are destined for a busy lifestyle consumer. The main concern using microwave heating is nonuniform temperature distribution, which may result in food safety problems. Consumers microwave a food product based on the time instruction provided on the package. A computational multiphysics model may be used to predict a time to reach the internal temperature sufficient to inactivate foodborne pathogens. The project contained three studies. The first study evaluated the physical and chemical properties of frozen white shrimp packed with 100% N2, 100% CO2, or mixture (70% N2 and 30% CO2). Air was used as control during one year of frozen storage. The second study objective was to develop and test a computational multiphysics model for predicting the temperature of frozen shrimp at a given time during microwave heating. A decoupled electromagnetics and heat transfer model was built using constant thermal and dielectric properties. The microwave model predicted that the average internal shrimp temperature could reach 99.4±1.7°C during 105 s microwave heating of frozen shrimp at four transient points. The expected average predicted temperature at 105 s was ~1.3°C lower than the actual microwave heating of 100 g shrimp. The third study aimed to inactivate Escherichia coli and Listeria innocua surrogate pathogens in ready-to-cook shrimp in a microwavable package with a microporous film (MF). Four treatments were evaluated, 50 and 100 g of frozen shrimp with non-film and with MF. Due to steam generated in the MF package, the inactivation time of L. innocua was reduced by nearly 15 s when 50 and 100 g of shrimp were microwaved. The study demonstrated that the computational multiphysics model could be used to predict internal temperature reaching up to 100°C. MF package could be a solution for generating uniform temperature distribution in frozen ready-to-cook shrimp during microwave heating.

Date

8-30-2022

Committee Chair

Sathivel, Subramaniam.

Available for download on Tuesday, August 28, 2029

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