Yes, irradiation does produce chemical changes in foods. They have been scrutinized by scientists in making safety assessments of irradiated foods. Any kind of treatment causes chemical changes in food. Scientists find the changes in food created by irradiation minor to those created by cooking. The products created by cooking are so significant that consumers can smell and taste them, whereas only a chemist with extremely sensitive lab equipment may be able to detect radiolytic products.
Irradiated food looks like the raw food.
Final regulations took effect in February for labeling irradiated raw beef and procedures for using the process to reduce or eliminate food-born pathogens on red meat. Consumers may soon see the international symbol for irradiation, a petal-like icon, on packages of beef in grocery stores. Until recently, only irradiated dried spices and enzymes were marketed in the United States. In January 1992, irradiated Florida strawberries were sold at a North Miami supermarket. Sales of irradiated products are ongoing in several grocery stores.