New foodborne pathogen identifying method shows “great promise”
The development project, which is being headed by researchers at Cornell University in the US, hopes to establish an alternative to the current methods used in the tracing of foodborne illnesses. It involves breaking up the DNA of bacteria samples and analysing their banding patterns.
Scientists using this current method often find that different strains of bacteria have genetically similar DNA fingerprints – making it difficult to differentiate between them.
But using the newly-developed method, researchers were able to quickly differentiate between the outbreak-related cases and non-outbreak related cases, and “identify small outbreaks that may not be easily detected with lower resolution subtyping approaches.”
Salmonella samples
Researcher professor Martin Wiedmann added: “The use of genome sequencing methods to investigate outbreak of foodborne bacterial diseases is relatively new, and holds great promise as it can help to identify the temporal, geographical and evolutionary origin of an outbreak.”
Recent foodborne outbreaks, such as the recent US cantaloupe-related listeria outbreak, which has killed 28 people and infected 133 across 26 states to date, have led to greater food safety awareness in the food production and packaging sector.
Researchers used samples from a Salmonella outbreak which originated in salami made with contaminated pepper between July 2009 and April 2010.
Of the 47 samples, 20 were collected from human sources during the outbreak and 27 were control samples collected from human, food, animal and environmental sources before the outbreak.
From 47 samples of the Salmonella bacteria, they were able to isolate four which they believed to be connected to the pepper contamination.
Apply to other pathogens
Through the development of the method, researchers inadvertently found links to a recent outbreak - a Salmonella strain linked to pistachio nuts in 2009 - and another un-established outbreak.
A similar method has previously been used in hospital settings to trace pathogens, but this is the first use of the method for foodborne illnesses.
Wiedmann and the Cornell University research team, who developed the single nucleotide polymorphism (SNP) test with the help of researchers at Life Technologies Corp, collaborated with researchers at Washington State University and New York City and State departments of health.
Professor Wiedmann added that he and his team are continuing to perfect the method and apply their development to other foodborne pathogens.
