May 24, 2010

US researchers collaborate for advance salmonella detection

Researchers at Iowa State University and a local company have been collaborating on a new and faster method of detecting salmonella in foods.

Using technology available through a local company, an Iowa State University researcher is working on a faster method to detect and genetically identify salmonella from contaminated foods.

Byron Brehm-Stecher, an assistant professor of food science and human nutrition, wants to replace the current system of salmonella detection with a new approach that can provide DNA sequencing-like results in hours rather than days.

Professor Brehm-Stecher's collaborator, Advanced Analytical Technologies, Inc., from Ames, is providing advanced biomedical instruments and reagents for the research.

The recent results of the research, funded by the Grow Iowa Values Fund, will be presented at the August meeting of the International Association for Food Protection in Anaheim, California.

Currently, definitive genetic identification of food-borne pathogens is done using traditional DNA sequencing methods first developed in the 1980s.

Professor Brehm-Stecher explained, "If you want (DNA) sequence information now, you first need to run a polymerase chain reaction (PCR) on total DNA extracted from a sample of contaminated food. This amplifies DNA from the pathogen you're looking for and will let you know if salmonella is present or not.

"However, further details about the pathogen are lacking, like what strain is present. To dig deeper, you need to run a cycle sequencing reaction - similar to a long PCR reaction – and send the output from this to a DNA sequencing core facility. Results are available about two days later.

"This is not fast enough to keep up with the pace of today's food production and distribution networks. We are able to get foods from the farm to the table - really any table around the globe – in a remarkably short period of time," he added.

Faster detection of specific strains can mean recognising an outbreak sooner and stopping tainted food from being delivered and consumed. The new method might be helpful for investigative agencies, Professor Brehm-Stecher said.