Title: Survival of Listeria monocytogenes and Salmonella spp. on catfish exposed to microwave heating in a continuous mode Authors
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: March 1, 2011
Publication Date: June 8, 2011
Citation: Sheen, S., Huang, L., Sommers, C.H. 2011. Survival of Listeria monocytogenes and Salmonella spp. on catfish exposed to microwave heating in a continuous mode [abstract]. International Microwave Power Institute (IMPI). June 8-10, 2011, New Orleans, LA. 1:1. Technical Abstract: Microwave (MW) heating using continuous output may provide better and consistent cooking for foods. Currently, household units with a build-in inverter device are available in which the output is continuous vs. the traditional on-off mode. With an inverter, these MW ovens may provide consistent heating at any specified power setting (e.g. 50%), instead of 50% on and 50% off during the time duration. Listeria monocytogenes (Lm, 4-strain cocktail) and Salmonella spp. (Sal, 6-strain cocktail) were surface-inoculated onto fish fillets (e.g. catfish) and then heated using an inverter-equipped MW oven to evaluate pathogen survival. Lm inoculated onto catfish was slightly more sensitive to microwave exposure than Sal. Greater than 5 log of Lm or Sal inoculation on catfish surfaces (fillet size 70 x 100 x 15 mm; weight 110-120g) could be totally killed in 2 min using a commercially available oven with a power of 1250 watt. The catfish surface-temperature at the beginning of the process was 10 deg C, and was about 80 deg C at the end of the process. Surface-temperature profile was monitored using an infrared sensor. Fillet yields were in the 75-85% range. Catfish texture was affected slightly early in the cooking process, approximately 15 s after heating, and the uneven heating may result in quality issue. The MW heating may become smoother by treating fish meat with phosphates and/or utilizing the Huang feedback control system which regulates MW power output. Current results indicate that applying MW energy for fish fillet cooking is feasible, and foodborne pathogens can be eliminated. Further, the results from a MW oven with built-in inverter can be used to design an industrial scale MW tunnel to process foods in a continuous energy output mode.