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CELS News Story Spring, 2007 Search for not-so-invisible ink can ensure your food is safe to eat By: Rudi Hempe, CELS News Editor and Reporter ---------------------------------------------------------Ever wonder how fresh that pre-packaged meat is in the grocer’s refrigerator? Ever wonder whether it was subjected to a food spoilage incident en route from the processing plant to the store? Spurred on by shocking news stories about contaminated and spoiled food, consumers are becoming increasingly concerned about food safety and questions like those above are not that unusual. Increasingly, people want assurance that the foods they buy are safe and of high quality and two chemists at URI are setting out to provide them with one tool that could give consumers peace of mind. Dr. William B. Euler, chair of the Department of Chemistry and Dr. Brett L. Lucht, a professor in that department, were awarded a CELS CARES (for Community Access to Research and Extension Services) grant recently by the College of the Environment and Life Sciences to further develop an ink for barcodes that will be a tattle-tale indicator whether the food product was subjected to higher than desirable temperatures. The award, one of nine given out by CELS for research projects, is unusual not only because of its subject but also because it was granted to researchers outside of the college.(The competition for CELS CARES research grants is open to all on the URI campus.) “In an increasingly complex food system, consumer protection is paramount,” says Dr. Nancy Fey-Yensan, assistant director for land grant programs and a professor in the CELS Department of Nutrition and Food Sciences. “This proposal addresses a unique and much needed approach to improving food safety which has significant potential to reduce food-borne illness and improve public health for all Americans. In fact, the technology Drs. Lucht and Euler propose could also easily be applied to improving the safety of a range of pharmaceutical and biological substances.” Euler and Lucht have been working on thermochromic pigments (pigments that change color when subjected to temperature changes) for years. It all started in 1998 when Dr. Otto Gregory, a URI professor of chemical engineering, called Euler one day. It seems there was a bake ware company in Georgia that approached URI seeking a pigment that could be added to the bake ware to indicate whether it was too hot to touch. Gregory asked Euler whether some polymers could be developed to provide the solution. Euler’s response was –“Of course, polymers can do everything!” Euler brought in Lucht because of his expertise in the field and they set out on the project. They encountered some difficulties. For example the bake ware company’s marketing department wanted a pigment that would turn red when it was hot and blue when it was not. That was a problem, relates Euler because the thermochromic pigments did not change to the colors desired by the marketing department or as Euler put it, “The physics did not cooperate with sociology.” Another problem was that there was no guarantee that the pigment would change colors repeatedly every time the bake ware was placed in an oven. But the big problem was trying to find a company that was willing to make the investment of scaling up the manufacturing of the pigment from lab to full-fledged production. Then about three years ago, Flint Ink (a major producer of inks for the printing industry) saw the Euler/Lucht website describing thermochromic pigments and contacted them. Flint Ink was interested in a thermochromic ink that could be applied to barcodes to indicate food spoilage on meat and dairy products. Once again the Euler/Lucht team got busy. The CELS CARES grant will help them fine-tune the ink. They currently are working with Accent Ink of Los Angeles (Flint Ink changed hands and they dropped their interest in thermochromic pigments but a new ink company, Accent Ink, decided to go forward.) How it works is this. A special barcode labeling machine using thermochromic ink deposits the ink and the code on the food product at the processing plant. If the food product is subjected at any time to temperatures that affect it adversely, the label changes-- a red bar appears rendering the UPC code incapable of transmitting data. A firm called Sira Technology will actually produce the system. At the processing plant special labelers will be needed. But at the other end—the markets— standard barcode readers can be used. Lucht said what remains to be done is to determine what range of temperatures is desired—whether there should be a sudden change in color or a gradual one. He says they may end up with several inks with different reference points. The thermochromic inks are not reversible—once the ink has been triggered by exposure to inappropriate temperatures, they cannot be changed back. Lucht says there are some time/temperature indicators already in use by the military. But these are stickers costing about $1 each –too expensive to be put on individual packages. Rather to save money, the military uses the stickers on large quantities such as case lots or whole pallets. The thermochromic pigments they are working on will be used in very small amounts affecting the price of the product by only one or two cents, they say. The same type of barcodes would be useful for other types of products such as biologicals and pharmaceuticals, says Lucht. But the greatest use will be for food products that are temperature sensitive. “This is a food safety tool for end consumers,” says Euler, “telling them whether the food has been stored properly from the processing plant to the store.”