Rapid Salmonella test designed to reduce meat and produce recalls.

Agricultural Research Service (ARS) scientists have developed an innovative test to detect Salmonella in ready-to-eat meats. The preliminary test--still being evaluated by agency researchers--relies on polymerase chain reaction (PCR) technology to detect food-contaminating microbes on a molecular level.

Food technologist Jitu Patel, of the ARS Food Technology and Safety Laboratory, and microbiologist Arvind Bhagwat, of the ARS Produce Quality and Safety Laboratory, in Beltsville, Maryland, compared their laboratory-developed "molecular-beacon" test with a commercial rapid-detection test currently in use. While both tests can detect Salmonella in eight hours, the laboratory test is less expensive than commercial kits.

To evaluate the efficacy of the new test, the scientists artificially contaminated various meats (turkey, bologna, and ham slices) and produce (mixed salad, sprouts) with S. enterica serovar Typhimurium and allowed the organism to incubate for 20 hours. Both tests were sensitive enough to detect contamination in the meat products at an estimated level of two to four cells per 25 grams. After a relatively brief incubation period of eight hours, both tests detected two to four cells of Salmonella in the 25-gram samples of meat as well as in the produce.

The ability of the molecular-beacon test to detect very low levels of Salmonella contamination in eight hours will aid the food industry in quality assurance, helping prevent recalls of contaminated meats and produce by stopping the products from being introduced into the marketplace. Detection of contaminated foods could be achieved within a work shift--before shipment takes place.