Effect of surrounding medium on radio frequency (RF) heating uniformity of corn flour

Radiofrequency Inactivation of Salmonella in Black Pepper and Dried Basil Leaves Using In-package Steaming

Radiofrequency (RF) heating has been extensively studied for pasteurizing low-moisture foods. Currently, bulk foods are treated with radiofrequency; potential cross-contamination may occur during packaging of pasteurized products. As an alternative, in-package RF processing was evaluated for Salmonella inactivation on black peppercorns and dried basil leaves and prevention of cross-contamination during storage postprocessing. In-package steaming refers to the process in which the samples were heated in a steam vent package to generate and retain steam during the treatment. This treatment achieved good heating uniformity which could be because of the circulation of steam within the package. One-way steam vent allowed the release of excess steam once a threshold pressure was achieved and later returned to its original position to seal the package, when the RF energy was removed. In-package RF steaming of black peppercorns and dried basil leaves for 135 s and 40 s, respectively, resulted in more than 5 log reduction of Salmonella. The steam vent remained stable posttreatment and properly sealed the package to protect the product from any external contamination. These results indicate that the use of steam vent could effectively pasteurize black peppercorns and dried basil leaves could be beneficial in preventing the potential cross-contamination postprocessing.

Sterilizing Ready-to-Eat Poached Spicy Pork Slices Using a New Device: Combined Radio Frequency Energy and Superheated Water

In this study, a new device was used to inactivate G. stearothermophilus spores in ready-to-eat (RTE) poached spicy pork slices (PSPS) applying radio frequency (RF) energy (27.12 MHz, 6 kW) and superheated water (SW) simultaneously. The cold spot in the PSPS sample was determined. The effects of electrode gap and SW temperature on heating rate, spore inactivation, physiochemical properties (water loss, texture, and oxidation), sensory properties, and SEM of samples were investigated. The cold spot lies in the geometric center of the soup. The heating rate increased with increasing electrode gap and hit a peak under 190 mm. Radio frequency combined superheated water (RFSW) sterilization greatly decreased the come-up time (CUT) compared with SW sterilization, and a 5 log reduction in G. stearothermophilus spores was achieved. RFSW sterilization under 170 mm electrode gap reduced the water loss, thermal damage of texture, oxidation, and tissues and cells of the sample, and kept a better sensory evaluation. RFSW sterilization has great potential in solid or semisolid food processing engineering.