Scientist develop new 2-in-1 test for E.coli detection in food

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Washington, March 24 (ANI): American scientists have developed a 2-in-1 test for detecting E. coli in ground beef and other foods.

The test, which can also help detect the toxins or poisons that the bacteria use to cause nausea, vomiting and diarrhoea, was described at the 239th National Meeting of the American Chemical Society (ACS) in San Francisco.

E. coli O157 may be present in food for hours or days before improper storage conditions allow them to grow and produce the toxins that actually cause food poisoning. Those toxins can remain in food even after the bacteria are dead and gone. Earlier, it took separate tests to protect against this double threat from the bacteria and the toxins.

Project leader John Mark Carter, who is with the U.S. Department of Agriculture's Agricultural Research Service in Albany, Calif., said: "Our test may be used in meat processing plants to allow in-house testing of products prior to sale.

"This would reduce the frequency of foodborne illness, reduce product recalls, and enhance public health while reducing annual cost for food testing."

While E. coli O157 outbreaks have involved foods such as lettuce, spinach, tomatoes, and peanut butter, ground beef remains a major concern. The bacteria may get into ground beef when meat is contaminated with faecal material from chickens or cattle during slaughtering or processing. If the meat is not properly chilled, the bacteria may multiply and produce enough of two main toxins - called Shiga toxin 1 and Shiga toxin 2 - to cause illness.

Until now, there was no two-in-one test for the bacteria and the toxins. Separate tests were required for each threat. Current tests for E. coli in beef also are time-consuming. The results take 3 to 5 days. But researchers say the new test cuts the waiting time to just 24 hours.

The new test uses microscopic plastic beads, each 1/100th the width of a grain of sand, containing a fluorescent dye. The beads, customized in Carter's lab, are coated with antibodies that lock onto proteins or antigens present on E. coli and its two main toxins. During the test, the beads are mixed together with ground beef or other food samples and then separated and run through an instrument. It identifies beads that have latched onto the E. coli antigens.

Carter said: "Finding a few E. coli bacteria in a large sample of ground beef or other food is like looking for a needle in a haystack.

"This new method makes the needle much easier to find, compared to standard methods. But improvements in sampling and sensitivity are still needed." (ANI)

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