Reuven Rasooly, a chemist at the United States Department of Agriculture’s Agricultural Research Service Western Regional Research Center in Albany, California (nice tagline) has developed a simple and inexpensive system for detecting Shiga toxin, a product of pathogenic Escherichia coli O157:H7.
The new system 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.