Indian-American develops bio-sensor to track food toxins
New York, March 4, 2008 (IANS)

An Indian-American has developed a revolutionary new bio-sensor capable of simultaneously screening thousands of food samples for deadly pathogens. Besides taking the pain out of such analysis, the technique would help neutralise potential threats and improve food-processing techniques, said Arun Bhunia, a professor of food science at Purdue University. The technology can recognise very small amounts of Listeria monocytogenes, a bacterium that kills one in five and the leading cause of food-borne illness.

"For food safety and bio-security purposes, you need a quick test - a first line of defence - to be able to tell if there is something pathogenic in the food or water," a report in Sciencedaily quoting Bhunia said. The technology utilises live mammalian cells that release a measurable amount of a signalling chemical when harmed. Optical equipment and computer software can then analyse this quantity to estimate the amount of harmful microbes present, Bhunia said.

"This is very important," he said. "With many toxins or pathogens, there is an effective dose or threshold you must pass before you have to worry. By providing information on quantity, this technology gives you a higher degree of confidence in the test and what steps must be taken to alleviate the problem."

The technology can recognise very small amounts of Listeria monocytogenes, a bacterium that kills one in five and the leading cause of food-borne illness. It also recogniSes several species of Bacillus, a non-fatal but common cause of food-poisoning, said Pratik Banerjee, a Purdue researcher and first author of a study detailing the technology that is published in the latest issue of the journal Laboratory Investigation.

By using live cells, called bio-sensors, this technology can identify actively harmful pathogens but ignore those that are inactive, or harmless. The new technology's discerning power also could help optimise processes to kill harmful microbes or deactivate toxins, Banerjee said. "When a large amount of pathogen is present, you can literally see the colour change taking place before your eyes," he added.

"This is the first time that anybody has trapped these kinds of cells alive in a collagen framework," Bhunia said.