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Mike Pariza (608) 263-7777
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.
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Bob Cooney