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Using microwave, acid treatments to kill pathogens, maintain meat's color

By Keener A. Tippin II



Daniel Y.C. Fung and assistant with food
Photo by April M. Blackmon.

Microbiologist Daniel Y.C. Fung and research assistant Erdogan Ceylan.



Meat processing plants can try washing, steaming, or any number of other ways to sanitize a carcass, yet the meat consumers purchase in the supermarket can still have that sickening and potentially deadly E. coli 0157:H7 bacteria.

Although effective, according to a K-State food microbiologist, most of these methods to reduce E. coli unfortunately occur on the front end of the processing procedure. Once the carcass is sliced into smaller portions, the meat can then be recontaminated, allowing microorganisms to grow and spread. Daniel Y.C. Fung is studying an approach that includes sanitation of the meat at the end of the processing procedure.

According to Fung, dipping the meat into an 80 degrees Celsius solution of lactic acid for a few seconds has been shown to kill 90 percent of microorganisms. After the meat is dipped into the solution it is immediately vacuum packaged and given short pulses of microwave treatments. Fung says data indicate these short pulses can kill another 10 percent of microorganisms on the meat's surface.

"The whole idea behind the microwave is after you vacuum package the meat and microwave it, it will remain uncontaminated until the meat goes to the retail store or the consumer," Fung said.

Fung said that while the acid bath may kill a lot of bacteria, if it is dipped or cooked in the microwave too long it will change the color of the meat. This discoloration from its natural red color may not be appealing to the consumer. Fung is experimenting to find the maximum time the meat can remain in the microwave and the maximum water temperature to retain its natural color.

"We're trying to find the best combination of where the color will not change or it will change a little bit but will still be acceptable to the consumer," Fung said, "but at the same time kill 90 to 99 percent of the microorganisms."

In previous studies, Fung has used smaller portions of meat. The current study, funded by the National Cattlemen's Beef Association, will examine the process using larger portions of meat.

Spring 2002

  • Updated: 8/23/16