Using Steam Without Cooking, New Device Kills Bacteria on Meat

Scientists with USDA's Agricultural Research Service have designed, built, tested and patented a device that kills bacteria on the surface of raw meat. Using steam, this simple, inexpensive method quickly kills Salmonella and other harmful microorganisms on poultry, fresh beef and pork without cooking the meat.

Patented in the United States and Canada (Patent No. 5,281,428), the new machine could be used easily in meat processing plant lines.

In just 25 milliseconds, the new machine kills 99.99 percent of bacteria by heating the meat surface with steam and cooling it in a vacuum. Harmful microorganisms usually dwell only on the surface of intact meat. One problem with using heat to kill the microbes has been that this cooks the meat's surface, giving it an appearance unacceptable to consumers.

ARS engineers Arthur Morgan (retired) and Neil Goldberg at the Eastern Regional Research Center in Wyndmoor, PA, developed the new machine. It surrounds a meat carcass with vacuum to withdraw all air, then flushes it with steam, treats it with a quick burst of 290 degree F steam, and vacuum cools it. The meat retains its raw appearance.

It has been difficult for industry to remove surface contaminants from meat because microorganisms escape hot-water washes or bactericide sprays and surfactants. Liquids can't reach all contaminated surfaces. Feather, hair or scale follicles are large enough to hide bacteria, but too small to admit a liquid wash or spray.

A commercial version of the machine could treat 4,000 birds an hour. One machine can serve an entire broiler processing line. Adding the equipment at the slaughterhouse is expected to add no more than 1 cent per pound to processing costs.

The full story appears in the October Agricultural Research, the monthly magazine of the Agricultural Research Service. The story is available on the World Wide Web at:

http://www.ars.usda.gov/is/AR/archive/oct97/steam1097.htm

Scientific contact: Michael Kozempel, USDA-ARS, Engineering Science Unit, Eastern Regional Research Center, Wyndmoor, Pa., phone (215) 233-6588, fax 233-6795, mkozempel@arserrc.gov.