Dr. Martin Wiedmann, a food science professor at Cornell University, along with a team of collaborators, have adopted a genomic approach to determine which strains of bacteria are responsible for food borne illness outbreaks. Published in the Applied and Environmental Microbiology journal, the researchers have been able to rapidly discriminate between outbreak-related strains and non-outbreak related strains by sequencing the genome of the bacteria that have been collected from human sources during an outbreak and those collected from human, food, and environmental sources before an outbreak.

Scientists have often found that different strains of bacteria have common DNA fingerprints that are too genetically similar to differentiate between them, making it difficult to establish whether the Salmonella that made one person sick was the same Salmonella that infected another person.  “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 said. “In particular, full genome sequence data may help to identify small outbreaks that may not be easily detected with lower resolution subtyping approaches.”  Wiedmann said he is continuing to perfect the method and use it to test other types of bacteria.  The U.S. Food and Drug Administration and other agencies are also starting to use similar approaches.