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GOVERNMENT AND SOCIETY Fresher food from Alaska Detecting contamination of food and drink used to take a few days. But it takes only a few hours with a new diagnostic technique developed by scientists at the U.K.’s Defense Evaluation and Research Agency (DERA) site at Porton Down and industry collaborators. DERA’s David Squirell expects a device to be on the market in two years and says it will be “applicable to most or all foods and beverages.” The device will be targeted for use by “semi-skilled personnel in production plants and distribution [centers], as well as environmental health officers,” he adds. DERA, entrepreneur David Owen, and the investment fund Circus Capital Technology have created Alaska Food Diagnostics, Ltd., to develop and market the diagnostic kit, which could have an important impact on staving off outbreaks of food poisoning by such pathogenic bacteria as Escherichia coli O157, Listeria, and Salmonella. The technique used is a spin-off of defense research developed to protect military personnel from biological weapons attacks and
further developed with the Central Science Laboratory of the Ministry of Agriculture, Fisheries, and Food. Because current diagnostics can take two to three days, foods such as dairy and meat products might already be on sale and may even be eaten before a problem is spotted. The Alaska device will be able to detect bacterial contamination in samples within a maximum of 8 h, which means that food manufacturers can dispatch products with short shelf-lives secure in the knowledge that they are safe. The new technique uses magnetic beads coated with bacterial antigen-specific antibodies to allow bacteria to be isolated from a food or beverage sample. A brief incubation period, in which bacteria can be concentrated, is followed by lysis of the cells using bacteriophages, a step that releases adenylate kinase (AK) from any actively growing bacteria. The addition of luciferase then reveals the amount of AK present as the measured intensity of bioluminescence. Standard tests take several days because the rate-
determining step is the incubation of large enough numbers of contaminating bacteria to allow detection. The Alaska technique, on the other hand, can work with a sample containing
