Scientists have created a new device that is able to concentrate foodborne salmonella and other pathogens faster than conventional methods, according to a study published in the journal Applied and Environmental Microbiology.

Researchers from the colleges of Engineering and Agriculture at Purdue University, Indiana, say the new system, called a continuous cell concentration device, could represent a potential tool for faster pathogen detection within the food industry.

According to the researchers, although the number of foodborne illnesses has declined in the past 15 years, the number of laboratory-confirmed cases of salmonella did not change significantly last year, compared with those in 2006 to 2008.

Researchers say this highlights the need for improved detection and prevention.

The new device works by using “hollow thread-like fibers” to concentrate the number of cells in test samples – the first step in the detection of foodborne pathogens.

Tested using samples of chicken, the machine breaks the meat down into the consistency of a milkshake, and the meat is chemically pretreated in order to prevent clogging of the filtering membranes.

The broken-down meat is then passed through 12 hollow-fiber filters around 300 microns in diameter. The filters are contained in a tube the size of a cocktail straw. This process is repeated until any pathogens present are concentrated enough to be detected.

Compared with current methods for this process which take a full day, the researchers say the new device can concentrate cells within 1 hour.

The system could make it possible for food processing plants to routinely screen food or water samples for pathogens within a single work shift, the researchers say.

Michael Ladisch, professor of agricultural and biological engineering at Purdue University, says:

This approach begins to address the critical need for the food industry for detecting food pathogens within 6 hours or less.

Ideally, you want to detect foodborne pathogens in one work shift, from start to finish, which means extracting the sample, concentrating the cells and detection.”

The device was found to concentrate inoculated salmonella by 500 to 1,000 times the original concentration. Furthermore, it was found to recover 70% of living pathogen cells in test samples.

“This is important because if you filter microorganisms and kill them in the process, that’s self-defeating,” says Prof. Ladisch. “The goal is to find out how many living microorganisms are present.”

The researchers say that this technique could be performed during food processing or vegetable washing before food products are shipped. They add that the device is also practical for commercial use as the tubes can be quickly cleaned between uses by flushing them with sodium hydroxide and alcohol.

However, before the device enters the commercial market, it must first undergo testing by the US Department of Agriculture.