Botulism assay quickly detects potent foodborne toxin
Though cases of botulism food poisoning aren't common in the United States today, they're nonetheless of concern to food safety researchers. That's why Agricultural Research Service biologist Larry H. Stanker and colleagues at the ARS Western Regional Research Center in Albany, Calif., developed a new, improved test for detecting what's known as "serotype A" of the toxin.
According to Stanker, the botulinum toxin that causes botulism occurs in seven different serotypes--A through G. A and B are culprits in most of the foodborne botulism cases in this country.
For decades, the "gold standard" of tests for detecting botulinum toxin has been an assay that requires laboratory mice. That assay takes at least four days to perform correctly, and is neither portable nor economical.
In contrast, the assay that Stanker and two Albany colleagues--biologist Luisa W. Cheng and research associate Miles C. Scotcher--have developed relies on laboratory-built molecules known as monoclonal antibodies, which can bind to the toxin.
Monoclonal antibodies that bind to serotype A toxin aren't new. But the ones the Albany team developed may be the most sensitive yet produced, capable of detecting the toxin in minuscule amounts. Stanker has formatted these antibodies into an assay that is 10 times more sensitive than the mouse assay, yet is easier to use and less expensive.
Stanker described the work in a 2008 article in the Journal of Immunological Methods, and now expects to complete assays for detecting serotypes B and E sometime this year. Already, he is working with Safeguard Biosystems, Inc., of San Diego, Calif., to package two of the serotype A antibodies into a dipstick-style test kit that looks and operates much like a home pregnancy test. The botulinum kit is intended for testing liquids, such as beverages, or clinical specimens, such as blood or urine.
Read more about this research in the May/June 2009 issue of Agricultural Research magazine, available online at: http://www.ars.usda.gov/is/AR/archive/may09/botulism0509.htm.
ARS is the principal intramural scientific research agency of the U.S. Department of Agriculture.