Author Description

Thermal pasteurization is an effective method to achieve food safety and extend the shelf life. But the heat applied also causes food quality degradation. It is equally necessary to ensure that the pasteurized food maintains the highest possible quality by selecting different pasteurization technologies or conditions. The goal of this research was to study the effects of thermal pasteurization on safety and quality of selected foods. Green beans and chicken livers were chosen as representative vegetable and protein-based food products. Processing conditions for the 915 MHz microwave-assisted pasteurization and conventional hot water pasteurization were designed to deliver two different levels of pasteurization, severe (F_90^10=10 min) and mild (F_70^7.5=2 min), for green beans. During the pasteurization, the green beans suffered significant losses in green color, chlorophyll, ascorbic acid, and total phenolics content. Microwave pasteurization caused significantly less degradation in green color, ascorbic acid, and total phenolics content than hot water pasteurization. The quality of green beans continued deterioration during storage at 10, 7, and 2 °C. The higher the storage temperature, the faster the quality deterioration. For both severe and mild pasteurization, microwave pasteurization showed superiority in preserving the green color of green beans both during pasteurization and post-pasteurization chilled storage. Thermal inactivation kinetics of Salmonella and Campylobacter in chicken livers during heating were studied to justify cooking recommendations for food safety. A parallel study on quality changes in chicken livers during heating was also conducted. Salmonella is more heat resistant than Campylobacter for chicken livers; thus, Salmonella should be selected as the target pathogen in designing thermal treatments of chicken livers. Validation tests confirmed that the D-values obtained could effectively eliminate Salmonella to ensure chicken liver safety.