Reheating is the thermal process to heat foods that have been previously cooked and cooled in a food service establishment. Proper reheating can eliminate a major portion of pathogens (disease-causing organisms). When reheating for hot holding, Time/Temperature Control for Safety (TCS) foods (aka potentially hazardous food or PHF) must be reheated to 165°F or above for 15 seconds. Ready-to-eat TCS foods prepared and packaged at a commercial facility must be heated to 135°F or above. Reheating food for hot holding should take no longer than 2 hours to ensure food safety. 

The more a food is processed, the greater the risks. When food is held, cooled and reheated, there is an increased risk from contamination caused by personnel, equipment, procedures and other factors. When food is cooked and cooled, the product goes through the temperature danger zone between 41°F and 135°F (optimal temperature range for microorganisms to grow) several times which also increases the risks.