Food safetyQuickly and accurately tracing food-borne outbreaks

Researchers have developed a new technique that could pinpoint the exact nature and origin of food-borne bacteria with unprecedented accuracy.

Currently, scientists trace food-borne illnesses by breaking up the DNA of bacteria samples into smaller pieces to analyze their banding patterns. This method often yields inconclusive results as different strains of bacteria share common DNA fingerprints and are too genetically similar to differentiate.

To overcome this challenge, Martin Wiedmann, an associate professor at Cornell University who specializes in analyzing food-borne disease pathogens, and his team of researchers used genome sequencing.

“The use of genome sequencing methods to investigate outbreaks of food-borne bacterial diseases is relatively new, and holds great promise as it can help to identify the temporal, geographical and evolutionary origin of an outbreak,” Wiedmann explained. “In particular, full genome sequence data may help to identify small outbreaks that may not be easily detected with lower resolution subtyping approaches.”

In his experiment, Wiedmann sequenced the genome of forty-seven samples of bacteria, twenty of which had been collected during a 2009 Salmonella outbreak. Using the other twenty-seven samples as controls, the team was able to quickly discern which bacteria led to the outbreak and which were un-related.

The genome sequencing test was created specifically to test for the bacteria from the 2009 Salmonella outbreak that sprang from salami contaminated by pepper. The research is still in its early phases and Wiedmann plans on perfecting the technique to test for other types of bacteria.