Electropolished Steel Might Positively Repel Bacteria

Bacterial film on poultry processing equipment might be prevented by a polishing treatment originally designed to give steel a showroom shine, according to an Agricultural Research Service scientist in Athens, Ga.

Microbiologist Judy Arnold found some potential food- safety benefits in a steel electropolishing process developed by Simmons Engineering Company, a poultry-plant machinery maker in Dallas,Ga. In electropolishing, steel gets an acid bath and then an electrical current is passed through it. In several studies, polishing, sandblasting and grinding have all reduced the buildup of "biofilm"--a matrix of microorganisms that have attached to each other. In Arnold's study, however, electropolishing seemed most effective.

Biofilms can be hard to remove even with chemical cleansers. In a poultry processing plant, biofilms can form if bacteria such as Salmonella move from carcasses to wet steel surfaces. These bacteria can multiply and infect other carcasses--a phenomenon called cross- contamination. Biofilm resistance would cut the need for sanitation chemicals.

Simmons Engineering Company had been concerned about reports linking biofilms and stainless steel. So company vice-president Wayne Austin contacted Arnold after learning she was testing various kinds of steel for resistance to bacterial attachment. She decided to include electropolished steel in her studies. Arnold works in the Poultry Processing and Meat Quality Research Unit, part of ARS' Richard B. Russell Agricultural Research Center in Athens. She suspects that electropolishing changes steel's electrical charge to positive, thus repelling the negatively charged bacteria.

Details are in a story in the February issue of ARS' Agricultural Research magazine. The story is also on the World Wide Web at:

http://www.ars.usda.gov/is/AR/archive/feb98/film0298.htm

Scientific contact: Judy W. Arnold, ARS Richard B. Russell Agricultural Research Center, 950 College Station Rd., Athens, Ga. Phone (706) 546-3515, fax (706) 546-3548, jarnold@negia.net.