Title 9 of the Code of Federal Regulations establishes prescribed thermal treatment for a variety of meat and poultry products. These requirements are to ensure the destruction of harmful microorganisms and viruses that cause diseases in humans and livestock. The information presented in this review provides information relative to the current procedures used by the Food Safety and Inspection Service (FSIS) for monitoring the adequacy of heat treatment of meat and poultry products; and the research activities that have been and are currently being conducted to develop new and/or improved methods for determining the maximum internal temperature of meat and poultry products. Currently, FSIS is using a protein “Coagulation Test” for monitoring the maximum internal temperature (MIT) of both beef and pork products heat processed to temperatures lower than 65°C; a residual “Acid Phosphatase Activity Method” for determining the MIT of canned hams, canned picnics and canned luncheon meat, and a third method, known as the “Bovine Catalase Test”, for the determination of catalase which gives a pass/fail indication at a cooking temperature of 62.8°C for rare roast beef and cooked beef. Since 1957, several attempts have been made to develop new and/or improved methods. These include an evaluation of the enzyme systems and various physical techniques. The lack of new and/or improved methods is not due to the lack of research efforts in this area, as evidenced by this review. The challenge is the development of a method which can accurately determine within ± 1.0°C the endpoint temperature in the temperature range (67.8 – 70.0°C) that is of most interest to FSIS.