AMES, IOWA – Researchers at Iowa State University researchers say a new technique for testing for Salmonella in produce may also have meat applications. Using a sampling method that utilizes the application of adhesive tape to food surfaces, the researchers believe the technique will provide food safety officials with more accurate and faster results during the investigation of foodborne illness outbreaks. The process was developed by Byron Brehm-Stecher, assistant professor in food science and human nutrition, and his graduate student Bledar Bisha, initially for produce applications, and utilizes ultraviolet light to identify the pathogen.

The tape is applied to the surface of the produce, then carefully removed, taking a sample of whatever is on the skin. That sample is then put on a slide and soaked in a special warm, soapy mixture that contains a genetic marker that binds with Salmonella and gives off a fluorescent glow when viewed under an ultraviolet light. Use of this genetic marker approach is called Fluorescent In-Situ Hybridization, or F.I.S.H.

The approach can tell investigators if the produce is contaminated with salmonella in about two hours.

When asked if this method could be used on meat or poultry, Mr. Brehm-Stecher answered, "We have only used it for produce at this point, but tape-based sampling techniques have been used previously for sampling of meats for subsequent deposition onto agar media for growth [Dr. Daniel Fung at Kansas State University has been active in this area].

"I believe that the tape-F.I.S.H. method could be used for sampling of additional surfaces [inanimate food contact surfaces, meats, etc.]," he added. "With the use of different organism-specific probes, it could also be adapted to detection of different pathogens on produce and other surfaces."

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