Food irradiation, a treatment of food by ionizing energy of gamma, electron beam or X-rays, with its unique advantages, is emerging as an important food processing method. It can be used for improving food security, ensuring food safety, and for obtaining market access by overcoming quarantine barriers to international trade. The need for reliable and routine testing methods to determine whether or not food has been irradiated has arisen as a result of the increased commercialization of the technology, growth in international trade in irradiated foods, and demand for labeling of the treated food by consumer organizations. This book provides an account of some scientific approaches for identification of irradiated foods treated with commercially relevant doses of radiation, based on Electron Spin Resonance Spectroscopy and Thermoluminescence techniques. The book describes the basic concepts of food irradiation technology, methodologies of identification, and experimental results. The book sheds light on the emerging field of food irradiation, and should benefit, food industry, regulatory agencies, and other stakeholders, and enhance confidence in the technology.