A
government researcher has developed a camera that can detect E. coli 0157:H7,
the deadly bacteria that poisoned many people in Walkerton, forced XL Foods of
Alberta into selling its beef-packing business and has bankrupted several U.S.
beef packers.
About
73,000 Americans get sick from the bacteria and about 60 have been dying every
year.
Reuven
Rasooly, a chemist at the United States
Department of Agriculture’s Agricultural
Research Service Western Regional Research Center in Albany, California
has developed a simple and inexpensive system that uses a camera and a
light-emitting source to detect active toxins.
Tests used
today cannot distinguish between the active and inactive form of Shiga toxin,
Rasooly says.
It’s
important to tell the difference between the two, because the toxin’s active
form poses a threat to humans while the inactive form does not.
“We need
devices that are affordable and sensitive to reduce the sources and incidence
of foodborne illness,” Rasooly says.
“Equipment
such as a commercial fluorometer, typically used to detect Shiga toxin and
other pathogens, is too expensive for developing countries, where the risk of
foodborne illness and outbreaks is greatest.”
In a study,
Rasooly and his colleagues showed that the camera system was as effective in
measuring Shiga toxin activity as a fluorometer.
Both
instruments had the same toxin detection levels. The difference is that a
fluorometer costs about $35,000 while the camera only costs $300, making it an
affordable alternative for diagnostic labs.
In
addition, the new system can easily be adapted for detecting other foodborne
toxins.
Rasooly
recently demonstrated that the camera system can be used to detect Aflatoxin
B1, a toxin produced byAspergillus flavus and Aspergillus
parasiticus.
“The toxin contaminates
crops and foodstuffs worldwide, affecting 4.5 billion people,” Rasooly says.
