CHAMPAIGN, Ill. - Scientists are zeroing in on a fast, reliable method to detect the presence of a bacterium that thrives in the meat people consume and in injuries suffered by humans and animals. In food, the bacterium -Clostridium perfringens - causes a 24-hour bout of abdominal cramps, diarrhea or nausea; in injuries, it is responsible for potentially fatal gas gangrene.
"This organism is probably among the top five causes of food-borne illnesses," said Hans Blaschek, a University of Illinois food microbiologist. "Any time you get a cafeteria entree that's been floating a while in meat sauce, Clostridium perfringens could be growing in it. It has an extremely rapid growth rate; it can double itself in 10 minutes. People can come down with abdominal cramps and nausea. It can cause people to lose time at work. They will think they have a flu bug."
Poisoning from Clostridium perfringens is among the most widely occurring food-borne illnesses in the United States, according to the U.S. Food and Drug Administration Center for Food Safety and Applied Nutrition. It often is unreported, but the Centers for Disease Control estimates that 10,000 cases occur each year. Victims usually have eaten in institutions where large quantities of foods are prepared. The bacterium - found in oxygen-starved soil, water, milk, dust, sewage and in human and animal intestinal tracts - can produce spores, which are activated during cooking.
Blaschek and Zonglin L. Liu, a visiting professor at the U. of I., have produced a monoclonal antibody-based ELISA (enzyme-linked immunosorbent assay) that quickly can detect small amounts of the alpha toxins produced in the early stages of the bacterium's growth. They reported their laboratory results in the June issue of the Journal of Food Protection.
Their method detected as few cells as 16 nanograms of toxin - about 1,000 cells - far below the million cells required to cause illness, Liu said. "This has great potential for the meat industry, where samples could be screened early for the presence of the organisms long before they replicate into numbers that can cause people to get sick," he said. "This could provide us a system that has not existed before."
Liu and Blaschek have presented their findings to meat processors, who in turn have expressed an interest in their method. "This process is more specific than other techniques being used today," Liu said. "Most other systems can recognize multiple organisms, but they can produce false readings because of contamination of the sample or misinterpretation of the material present in a sample."
The research began under an Army grant with the goal of developing a technique to identify mutants of the bacterium, which were suspected as a component of biological warfare during the Gulf War. Gas gangrene can occur in and worsen deep-tissue wounds. When funding for the grant ended, the researchers continued their work, with university support, looking at the problem as a food-safety issue.
Liu and Blaschek have begun adapting their technique for testing meat products. They hope that with minor modifications it also could quickly detect other food-borne toxins.
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