Temperature Control and Time-Temperature Abuse
Temperature control and time-temperature abuse
This domain tests the danger zone, cold and hot holding limits, cooking temperatures, cooling and reheating rules, thawing, and thermometer use. Ontario questions often give a temperature and a time and ask whether the food is safe, must be reheated, or must be discarded.
Core rules
- The danger zone is 4°C to 60°C (40°F–140°F). Keep cold food at 4°C or colder and hot food at 60°C or hotter.
- Cooking minimums (internal temperature): poultry, stuffed foods, and dishes containing poultry 74°C (165°F); ground meat 71°C (160°F); whole cuts of beef, pork, lamb, and veal 63°C (145°F) with a rest time; fish 70°C (158°F) or until opaque and flaky.
- Cooling: from 60°C to 20°C within 2 hours, then from 20°C to 4°C within 4 hours-6 hours total. Use shallow pans, ice baths, blast chillers, and loose covers.
- Reheating: heat to 74°C (165°F) quickly, within 2 hours, and reheat only once. Do not use hot-holding equipment to reheat.
- Thaw under refrigeration at 4°C or colder, under cold running water, in a microwave immediately before cooking, or as part of cooking. Never thaw on a counter.
- Use a probe thermometer, sanitize the stem, take the reading in the thickest part, and calibrate in ice water (0°C) and boiling water (100°C).
Worked example
A pot of chili is cooked at 11 a.m. and left on the stove until 3 p.m.; the centre reads 38°C. It has been in the danger zone for four hours. Because cumulative time above 4°C exceeds the two-hour limit used in Ontario food handler training, the chili should be discarded-not reheated and served. Reheating to 74°C may kill bacteria but will not destroy toxins already formed, and the time-temperature abuse is the critical failure.
Traps
- Reheating fixes nothing if toxins or spores have already formed.
- Hot holding at 60°C still requires time limits and records.
- A surface reading, or a reading with an unsanitized probe, is unreliable.
- The danger zone is not 5–57°C or room temperature only.