Microbiological Validation of Microwave‐Circulated Water Combination Heating Technology by Inoculated Pack Studies

A 915‐MHz Microwave‐Circulated Water Combination (MCWC) heating technology was validated for a macaroni and cheese product using inoculated pack studies. Before the tests, heat resistances of a Clostridium sporogenes (PA 3679) spore crop were determined in neutral phosphate buffer and macaroni and cheese product. Trays of macaroni and cheese products were subjected to 3 processing levels: target process (F 0 = 2.4), under target process (F 0 = 1.2), and over target process (F 0 = 4.8). The inoculated packs were evaluated by count‐reduction method and end‐point method. The microbial results showed that microbial destruction resulting from MCWC heating technology matched the calculated degree of sterilization (F 0 value). This study suggests that the MCWC heating technology has potential in sterilizing packaged foods.