Survival of Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella spp. on Catfish Fillets Exposed to Microwave Heating in a Continuous Mode
Article first published online: 3 AUG 2012
© 2012 Institute of Food Technologists®
Journal of Food Science
Volume 77, Issue 8, pages E209–E214, August 2012
How to Cite
Sheen, S., Huang, L. and Sommers, C. (2012), Survival of Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella spp. on Catfish Fillets Exposed to Microwave Heating in a Continuous Mode. Journal of Food Science, 77: E209–E214. doi: 10.1111/j.1750-3841.2012.02817.x
- Issue published online: 3 AUG 2012
- Article first published online: 3 AUG 2012
- MS 20120350 Submitted 3/6/2012, Accepted 5/19/2012.
- E. coli O157:H7;
- fish fillets;
- L. monocytogenes;
Abstract: Microwave (MW) heating using continuous power output with feedback control and a modified ingredient formulation may provide better and consistent cooking of foods. Currently, household units with build-in inverter power supply units are available. These new generation MW ovens provide continuous, adjustable output and cooking, in contrast to the traditional rectifier-based ovens that rely on the on–off mechanism for control. This study attempted to apply a feedback power control (termed as modified or “smart” MW oven) and phosphate treatment to further improve heating uniformity and enhance food quality and safety. Listeria monocytogenes (Lm, 4-strain cocktail), Escherichia coli O157:H7 (Ec, 5-strain cocktail), and Salmonella spp. (Sal, 6-strain cocktail), surface inoculated onto catfish fillets (75 × 100 × 15 mm; weight 110 g), were heated using the modified MW oven to study the inactivation of the pathogens. The sensitivity of these 3 bacteria to MW heating was in the order of Ec (most), Lm, and Sal (least). Greater than 4 to 5 log CFU reductions of Ec, Lm, or Sal counts on catfish fillet surfaces were inactivated within 2 min of 1250 W MW heating, where the fillet surface temperature increased from 10 to 20 °C to 80 to 90 °C. MW heating caused degradation of catfish fillet texture, which was noticeable as early as 10 to 15 s after the heating started, as evidenced by bumping sounds. Bumping can be significantly reduced by soaking fillets in phosphate solution. However, the results may need verification if applied in different MW ovens and/or with foods positioned away the geometric oven center. This study successfully demonstrated the feasibility of applying MW energy to eliminate foodborne pathogens on fish fillets.
Practical Application: The results demonstrated in this report with the “smart” microwave oven design may enhance microwaveable food safety and quality, and therefore promote the microwaveable food business.