ARS | Publication request: Elimination of Salmonella in Microwaveable Non-Ready-to-Eat Meats by Power-Controlled Microwave Heating

Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: April 5, 2010
Publication Date: July 14, 2010
Citation: Huang, L. 2010. Elimination of Salmonella in Microwaveable Non-Ready-to-Eat Meats by Power-Controlled Microwave Heating. Meeting Abstract. ISSN:1070-0129.pg.62-66.

Technical Abstract: Microwaveable non-ready-to-eat (NRTE) foods belong to a category of products that contain raw ingredients (such as chicken meats). These products are usually frozen and heated in a microwave oven prior to consumption. As the products are not uniformly cooked during microwave heating, human pathogens, such as Salmonella in raw chicken meats, may survive and cause foodborne poisoning. A recent outbreak involving a frozen chicken NRTE product caused 139 cases of foodborne salmonellosis in 30 states in 2007. The objective of this research was to develop a microwave heating process to eliminate Salmonella in microwaveable NRTE foods. An inverter microwave oven (1.25 KW 2.54 GHz) was modified with a feed-back power control mechanism to accomplish this goal. An infrared temperature sensor was used to monitor the temperature of samples during microwave cooking. The heating process was divided into two stages. In the first stage, microwave heating was used to increase the surface temperature of food samples to a temperature set-point, and then continued with 10% of the total power output in the second stage. A frozen simulated NRTE product was prepared by packaging 150 g gravy with raw chicken meats (2.54 × 2.54 × 1.27 cm, 50 g), which were pre-inoculated with a Salmonella cocktail. Partially thawed samples were cooked in the modified microwave oven. The temperature set-point in the first stage was 70, 75, 80, or 85 C. The heating time in the second stage ranged from 1 to 4 min. With an average initial concentration of 6.5 log cfu/g of Salmonella in raw chicken meats, the product was free of Salmonella after a 3 min heating in the second stage if the samples were heated to a set-point above 75 C in the initial stage. This research demonstrated that this microwave heating process was capable of eliminating Salmonella in NRTE foods.