New detection method for food toxins found

Published 27 August 2008

Japanese researchers develop new technique to detect toxins in food; the method involves artificially produced human enzymes that act as sensors for toxins in food samples

A research group led by the Kobe University Research Center for Environmental Genomics has developed a technique that may enable faster and more accurate detection of toxic substances in food, the Yomiuri Shimbun reports. The technique, which is not yet ready for widespread practical use, involves artificially produced human enzymes that act as sensors for toxins in food samples.

Currently methods of food toxin analysis, such as chromatography and experimentation on mice, can take weeks to complete, a time frame the new technique could reduce to a few days. The researchers are working to further improve the accuracy of the new approach.

The research group was formed in October 2006 comprising the university, the National Institute of Advanced Industrial Science and Technology in Tsukuba, Ibaraki Prefecture, and the wine maker Mercian Corp., based in Chuo Ward, Tokyo. The enzyme used is cytochrome P450, which alters its chemical structure when it comes into contact with certain toxic substances. The enzyme, which has fifty-seven variant forms, is present in the human body and functions to detoxify it of harmful substances, according to Prof. Hiromasa Imaishi of Kobe University, the head of the team. The team genetically engineered several types of the enzyme from coliform bacteria for use as sensors in the research.

New technology developed by the group enabled the enzymes to be attached to glass slides. When a contaminated food sample is placed on it, the treated slide gives off a fluorescent reaction that is easily captured by a highly sensitive camera. Successful experiments using food contaminated with benzopyrene, a carcinogen found in automobile exhaust, confirmed the effectiveness of the sensor.

The researchers said the technique could be used to detect such harmful substances as methamidophos, an organic phosphate that has been found in frozen gyoza dumplings made in China, and malachite green, a synthetic antibacterial drug that has been found in grilled eel. The drawbacks of other food toxin detection techniques include the time required to analyze research results, and the variation between the reactions of individual mice to different toxins. “Developing a fast, accurate technique that can be put into practical use is an urgent task. In the wake of food poisoning cases related to frozen gyoza dumplings, consumers are losing faith in food safety,” Professor Imaishi said.