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Wong Receives Pound Research Award

Many of us have some experience with one of Amy Wong”s research interests and none of us has pleasant memories of the experience. Wong studies enterotoxins produced by Staphylococcus aureus and Bacillus cereus. We know them as sources of food poisoning.

Her work with enterotoxins and biofilms has earned this food microbiologist a Pound Research Award for 1997.

Five major kinds of enterotoxin H, produced by Staphylococcus aureus, have been identified so far; however, about 5 percent of staphylococcal foodborne outbreaks are caused by unidentified enterotoxins. Wong started her research career seeking to isolate, and has successfully identified, one of these mystery toxins.

Once a toxin is purified and identified, researchers can develop antibodies that detect that toxin, she explains. Then regulatory agencies and food processors can use these tests to monitor foods, making sure they”re safe.

Wong”s main focus now is a Bacillus cereus toxin. The toxin is composed of three different proteins, all required for biological activity. Following up on Food Research Institute work started in the 1970s, Wong purified the diarrheal toxin produced by Bacillus cereus, which led to development of specific immunological assays and a simple blood agar test for detecting the toxin. She has also shown that this toxin is involved in a serious eye infection caused by Bacillus cereus, and is investigating the toxin”s mode of action.

We probably don”t think much about biofilms, which are Wong”s other research interest. Biofilms consist of microorganisms attached to a surface dental plaque is one example. When spoilage organisms and pathogens form biofilms on food-processing and handling surfaces, we can wind up with spoiled food and sick people

Biofilms are a major concern for food processors. For example, Lactobacillus casei, a common contaminant in cheese-processing plants, can form biofilms on cheesemaking equipment, and competes well with cheese starter cultures. Too much L. casei can cause calcium lactate haze, which looks like mold, on cheese. Wong, in collaboration with Mark Johnson at the Center for Dairy Research, showed that Wong”s work showed that regular cleaning and sanitizing may not eliminate L. Casei biofilms; cheesemakers need to steam-clean their equipment to kill it. She has also worked with Doug Reinemann of the CALS milking lab to develop methodology and assess air-injected clean-in-place systems for removing milk-soils and biofilms on milking equipment.

Wong is currently using Salmonella typhomurium as a model to study biofilm formation, hoping to find out what helps bacterial cells stick to surfaces and one another to form the film. Knowing what makes them stick should help researchers develop treatments to keep the cells from sticking together. A surface treatment that inhibits biofilm formation on stainless steel and rubber gaskets would be a boon for dairy farmers and cheesemakers. It would greatly reduce the time and expense of cleaning milking and milk-processing equipment.

Wong”s record of research accomplishment ranges from basic (protein purification and characterization) to applied (development of assay methodologies, control of biofilms) an approach that truly encompasses the Wisconsin Idea.