USDA funds nucleic acid test for Salmonella contamination detection

Mark A. DeSorbo

DENVER—Xtrana Inc., a developer of nucleic acid-based technologies, has received a Small Business Innovation Research Phase 1 grant from the U.S. Department of Agriculture to create a test to detect Salmonella contamination in food.

News of the funding in late June came on the heels of Xtrana receiving a U.S. patent for the test technology, number 5,989,813, “Detection of Amplified Nucleic Acid Sequences Using Bifunctional Haptenization and Dyed Microparticles.”

“The test is DNA based,” says Xtrana's Chief Executive Jack Wheeler. “We are looking for specific messenger RNA expression, a DNA fingerprint, so to speak, that is only expressed by Salmonella. The test is sensitive enough to detect down to the hundreds of bacteria—more sensitive and specific than traditional microbiology acids.”

Xtrana is also developing nucleic acid tests for E. Coli 0157:87, a specific strain of the bacteria that is particularly deadly; Listeria, a pathogen found in milk and cheese; and coliforms, microorganisms found in water.

Salmonella, however, is the most common bacterial cause of food-borne illness. During slaughtering and processing, salmonella may contaminate animal carcasses. The USDA estimates that nearly 40 percent of the American poultry supply, 12 percent of the pork and 5 percent of the beef are contaminated with salmonella. Fresh fruits and vegetables have been also implicated in outbreaks of salmonellosis.

The test for salmonella contamination, Wheeler says, will be rapid, inexpensive and user-friendly to meet the demands of on-site testing in the food processing and packaging industries. The test, he says, will accommodate high sample throughput with a turnaround time of less than one day. It will also incorporate Xtrana's Xtra Bind nucleic acid binding matrix and lateral flow technology, which is integrated into a modular platform of the company's Self Contained Integrated Particle system.

“Usually, a 25-gram sample of meat is used. The meat is cultured for 4 to 6 hours, and once that's done, a sample is taken and tested to see if [salmonella] exists. We're hoping these test, once approved, will be marketed by more specific companies.”

At the time of this report, Biopool International, a supplier of human diagnostic equipment based in Ventura, CA, was slated to complete the final stages in the acquisition of Xtrana. Since incorporation, Xtrana has received about $3.1 million in funding from the federal government and $1.2 million from the private equity sales.


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