Algorithm detects harmful bacteria

Algorithm detects harmful bacteria

PORK producers can now rely on a new kit to examine meat that is suspected of being contaminated with pathogenic bacteria.

The technique was developed in a European Union-funded project called Biotracer. It relies on mathematic algorithms to pinpoint the most likely origin of harmful bacteria on meat, such as salmonella.

"You can use the math modeling to say that it's 90% certain that the contamination came from the raw materials, or you could say that it's almost certain that it was a particular slicer in the boning hall," according to Kieran Jordan of Teagasc, the Irish agricultural research institute, in Dublin, Ireland.

A Dutch pork facility was used as a test bed for the detective-style investigation of salmonella contamination. The technique works by tracing the strain and its whereabouts and could help prevent having to shut down the entire processing facility for a deep clean. This approach involves fingerprinting contaminant bacteria thanks to DNA profiling and identifying its origin.

"It is not good enough to just say (bacteria) are present; you must be able to say how many. You also need to do typing of strains (for identification)," Jordan said.

Previous methods were not so precisely targeted.

Contamination of meat "can occur when equipment is colonized by biofilms of salmonella living and growing on equipment that can be difficult to clean, such as de-hairing machines," Rob Davies, a salmonella expert with the U.K. Animal Health & Veterinary Laboratory Agency in Weybridge, U.K., said. "The critical thing is very regular cleaning and disinfection to avoid this. Once a complex mixture of different bacteria and accumulated organic material form a biofilm, it is more difficult and more resistant to disinfectants."

This improved, faster detection method is not restricted to pork or to salmonella, the announcement said. It is also applicable to other harmful microbes in food such as helicobacter in chicken and listeria in cheese, Jordan explained.

"It is the math behind the method that makes a difference," he added. "It could even be used by forensic detectives."

"It was a very ambitious project," noted food scientist Mansel Griffiths of the Canadian Research Institute for Food Safety in Guelph, Ont. However, "it did succeed in identifying novel approaches to identify and trace sources of contamination of food that is imperative to ensure the safety of consumers."

According to Griffiths, who was chair of the project's international expert advisory committee, the best way to develop more effective control strategies for any foodborne pathogen is to gain a better understanding of how such a pathogen functions, i.e., its physiology, how it relates to its environment (its ecology) and how it affects foodborne disease progression (its epidemiology).

"There has been a lot of good work done in the project, but the value will come in how it is employed," Davies said. "If it just stays in research reports, that will not be much help. (However,) if it is taken up by Europe to identify sources of contamination in a way that can reduce human illness, then it could begin to pay for itself."


Volume:85 Issue:04

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