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On-Farm Testing for Pathogens on the Horizon

Researchers are creating a new system for rapid on-farm detection of pathogens. Such an achievement could usher in a new age of agricultural diagnostics, allowing the detection of tiny, potentially harmful organisms before they leave the farm and get into the food chain.

Agricultural Research Service scientist Michael Perdue and his Animal Waste Pathogen Laboratory team are collaborating with researchers at Idaho Technology, a company based in Salt Lake City, Utah, to design fluorescent probes and primers to identify specific genetic sequences in 30 to 45 minutes--far faster than is currently possible. Current culture techniques require 18 hours to several days to unequivocally identify pathogens in the laboratory. The relatively new genetic analysis technique, called fluorescent real-time polymerase chain reaction (PCR), is used with investigator-designed probes and primers to rapidly pinpoint short stretches of each pathogenic organism's genetic code.

In addition to quick results, the detection system would be portable and could be brought to the farm or any other location. Regulatory agencies, farmers, consumer groups and industry groups could all benefit from the nearly immediate assessment of the presence of pathogens in a number of settings, whereas previously, days could pass prior to identification.

Before this new age of detection can proceed, researchers have to evaluate a host of different primers, using real-life organic substances as test samples, to determine the usefulness of real-time fluorescence-based PCR machines.

Researchers will analyze substances such as milk, soil, water and manure for the presence of pathogenic organisms like Salmonella, Listeria monocytogenes, E. coli O157:H7, hepatitis viruses (A and E), and bovine enteric viruses.

ARS is the U.S. Department of Agriculture's chief scientific research agency.