ARS scientists have developed two new methods of
detecting ractopamine, a feed additive promoting leaner meat, in livestock.
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New Tests for Detecting Livestock Growth
Promoter By Jan
Suszkiw April 14, 2004
A feed additive given to cows and pigs so they'll produce leaner
cuts of meat can now be detected by two new methods, according to
Agricultural Research Service
scientists.
Weilin Shelver and David Smith developed the methods as a
faster, more user-friendly alternative to high-pressure liquid chromatography
(HPLC). This procedure is the chief means by which federal inspectors now
determine residue concentrations of the additive, called ractopamine
hydrochloride, in live animals or carcasses of butchered animals.
Such testing is deemed crucial to national food safety programs
aimed at protecting consumers from misuse of ractopamine and other animal
drugs. For example, the tolerance level for residue in pig muscle is 0.05 parts
per million. Testing also is done to certify meat products, such as for export
to member nations of the European Union. The union does not allow animal growth
promoters.
Although effective, HPLC testing can be a laborious,
time-consuming and costly affair, according to Shelver, who, along with Smith,
is at the ARS Red River Valley
Agricultural Research Center, in Fargo, N.D. There, she and Smith developed
two kinds of tests using a monoclonal antibody, a specialized protein that
binds with molecules of ractopamine in urine or tissue samples so it can be
detected. The first method is an enzyme-linked immunoabsorbent assay (ELISA).
The second is based on an optical biosensor.
In trials at Fargo using urine samples from ractopamine-fed cows
and sheep, the ELISA and biosensor performed as well as HPLC in detecting the
drug at concentrations of five to 19 parts per billion. The ELISA method yields
the quickest results, since it can analyze many samples simultaneously--100 in
five hours, for example. The biosensor worked best with low numbers of samples
that require sequential analysis, such as on a production line at the rate of
one every 10 minutes.
The ractopamine monoclonal antibody has been patented to
encourage its commercial development by industry.
Read
more details on the research in this month's issue of Agricultural
Research magazine.
ARS is the U.S. Department of
Agriculture's chief scientific research agency. |