A thermochromic ink that changes color at high temperatures now offers food manufacturers a more reliable coding method, with a more obvious color change, to indicate correct sterilization of packaged food products.    Designed for retort sterilization of filled cans or plastic pouches, the ink changes from black to blue when the food package reaches the correct temperature of between 115 and 125oC.    With the growing regulatory demands by governments for proper coding and marking on co...