Outbreaks of food poisoning could be a thing of the past thanks to a diagnosis instrument that is being developed as the result of a joint venture between Porton Down’s Defence Science and Technology Laboratory (DSTL) and Alaska Food Diagnostics.
With current microbiological methods, the two or three days required to identify contaminated produce mean that food may have been eaten by the time test results are obtained.
The new instrument, however, will enable contaminated samples to be identified within a maximum of eight hours, allowing food manufacturers to release even short shelf life products to market knowing they are safe.
The diagnostic instrument will detect pathogenic bacteria in foods, beverages and throughout the food distribution chain. Bugs such as E.coli O157, which has recently caused a number of food poisoning outbreaks, Listeria monocytogenes and Salmonella can all be detected using the technique.
The technology uses magnetic beads coated with antibodies which pick up specific bacteria from a food slurry. Next, a magnet is used to separate the beads from the food, and they are incubated to ensure that any bacteria present are actively growing. Special viruses called bacteriophages are then added to the mixture. These bacteriophages attack the target bacteria and break them open releasing an enzyme called Adenylate Kinase (AK).
Firefly luciferase is then added to react with the AK and produce light. The amount of light produced is assessed to determine which bacteria might be present in the food.
Normal test methods rely on having to grow the usually low numbers of contaminating bacteria to high levels before they can be detected, since classical detection techniques are not very sensitive and require 100 million bacteria to be present before they are effective. The new, highly sensitive method, on the other hand, can detect less than 100 bacteria, meaning very short incubation steps are required resulting in a much shorter time to get results.
The process is also being touted as a method for testing hospital samples to decide which antibiotic might suit a patient best. The company said that a working prototype should be available within a year.