
New Tests Nab ToxinsBy Linda
McGraw February 16, 1999New tools to detect mycotoxins that
contaminate corn, barley, wheat and other commodities have been developed by an
Agricultural Research Service scientist.
ARS is USDAs chief scientific research
agency. Fungi that grow on these crops produce the toxins. One of the more harmful
ones is aflatoxin, produced by the fungus Aspergillusflavus.
Aflatoxin takes its greatest toll on U.S. corn production during drought and
excessively high temperatures. Law prohibits the sale of corn--or any grain--for human consumption if it
contains more than 20 parts per billion of aflatoxin. For domestic
non-milk-producing animals, the permissible level ranges from 100 to 300 ppb. Inspectors need accurate and sensitive tests to detect such minute levels.
Thats why ARS chemist Chris M. Maragos in Peoria, Ill., has developed
several new tests that more accurately detect the toxin. One is a new antibody for an existing ELISA test (enzyme-linked
immunosorbent assay). The antibody selectively binds with aflatoxin. If the
sample is free of aflatoxin, the technician sees a deep orange color. If toxin
is present, there is no color. Another tool, capillary electrophoresis, separates compounds based on their
electrical charge. This test doesnt require chemical solvents used by
traditional analytical methods. Maragos adapted capillary electrophoresis to
measure another type of mycotoxin--deoxynivalenol, commonly called vomitoxin,
or DON. DON is associated with wheat scab, a problem that has cost wheat
growers around $3 billion in losses over the last 3 years. An article describing the tests appears in the February issue of ARS
Agricultural Researchmagazine. The story is also on the World Wide Web at: http://www.ars.usda.gov/is/AR/archive/feb99/toxin0299.htm Scientific contact: Chris M. Maragos, ARS
National Center for Agricultural
Utilization Research, Peoria, Ill., phone (309) 681-6686, fax (309)
681-6686, [email protected].
U.S. Department of Agriculture | |