SOPs for holding, cooling, freezing, thawing and reheating
Keep food out of the danger zone: hot at 63 °C or above, cold at 5 °C or below, cool fast, thaw in the fridge, reheat to 75 °C.
The danger zone and why time matters
Bacteria multiply rapidly between about 5 °C and 60 °C, the danger zone (the limits used in WHO's Five Keys to Safer Food). In ideal conditions some can double about every 20 minutes. Some, like Bacillus cereus in cooked rice and Clostridium perfringens in large pots of meat curry or gravy, form spores that survive cooking and grow when food cools slowly. So every SOP in this topic aims to keep food out of the danger zone, or to pass through it as fast as possible. Use a clean, sanitised, calibrated probe thermometer at the centre or thickest part of the food, and record each reading. Temperatures here are the limits commonly used and taught. FSSAI's Schedule 4 for caterers gives close figures: hot holding at 60 °C or above, reheating to above 74 °C, cooking meat to a core of 75 °C, and cooling to 21 °C within 2 hours. Always follow your unit's validated limits.
SOP limits at a glance
| Step | Key limit (commonly used) | How | If the limit is not met |
|---|---|---|---|
| Hot holding | 63 °C or above (FSSAI Schedule 4: 60 °C or above) | Preheat bain-marie or hot case; hold only fully cooked food; check and record at set intervals (e.g. every 2 hours) | Below 63 °C for under 2 hours: reheat to 75 °C and return. Longer or unknown: discard |
| Cold holding | 5 °C or below | Pre-chill the display; ice up to the level of the food; small batches out at a time | Find the cause; chill at once; discard if the time above 5 °C is unknown or too long |
| Cooling | About 60 °C to 21 °C within 2 hours, then to 5 °C within the next 4 hours | Shallow pans, small portions, ice bath, stirring, blast chiller | Reheat to 75 °C and start cooling again, or discard |
| Freezing | −18 °C or below | Freeze in small, labelled, dated portions; do not overload | If food has thawed, do not refreeze it raw; cook it or discard it |
| Thawing | In the refrigerator, at 5 °C or below | Covered tray on the bottom shelf; plan a day ahead for large items; cold running water or microwave only if cooked at once | Food thawed on the counter at room temperature: discard |
| Reheating | At least 75 °C at the centre, quickly (FSSAI Schedule 4: above 74 °C) | Reheat on the stove or in an oven, stirring; reheat only once | Keep heating until 75 °C; discard if it cannot be reached |
Draw it: cook, cool, store, reheat
The two-stage cooling rule as commonly taught; FSSAI's Schedule 4 for caterers also asks for cooling from 60 °C to 21 °C within 2 hours. Follow your unit's validated limits.
SOP: cooling cooked food (two-stage rule)
- 1Start cooling as soon as cooking ends; never leave a large pot to cool on the stove.
- 2Divide food into shallow pans or small portions; cut large joints.
- 3Speed it up: ice-water bath, stirring, or a blast chiller; leave loosely covered until cool.
- 4Stage 1: food must reach 21 °C within 2 hours.
- 5Stage 2: food must reach 5 °C or below within the next 4 hours (6 hours in all).
- 6Cover, label and date, and store in the refrigerator.
- 7Record times and temperatures; if a stage is missed, reheat to 75 °C and restart, or discard.
SOP: thawing and reheating
- 1Plan ahead: move frozen food to the refrigerator a day before for large items.
- 2Thaw in a covered tray on the bottom shelf, away from ready-to-eat food. Never thaw at room temperature on the counter.
- 3Cook thoroughly once fully thawed; do not refreeze thawed raw food unless it is cooked first.
- 4Reheat quickly until the centre reaches at least 75 °C; stir for even heating.
- 5Do not use the bain-marie or hot case to reheat; it is for holding only.
- 6Reheat only once; discard leftovers that are not used after reheating; record the temperature.
Hospital, hostel and school noon-meal kitchens cook large batches of rice, sambar and dal. Cooling them fast in shallow pans and reheating to 75 °C stops Bacillus cereus and Clostridium perfringens from making patients and children ill.
2 marks: “What is the danger zone?” The temperature range of about 5 °C to 60 °C (WHO) in which bacteria multiply rapidly; food should pass through it quickly or be kept out of it.
5 marks: “Explain the two-stage cooling rule and the SOP for thawing.” Cool from about 60 °C to 21 °C within 2 hours, then to 5 °C within the next 4 hours, using shallow pans and ice baths. Thaw in the refrigerator, never at room temperature; do not refreeze raw thawed food.
10 marks: “Write SOPs for hot holding, cold holding, cooling, thawing and reheating of food in a food service unit.” Danger zone; limits table; cooling steps; thawing and reheating steps; thermometer use, records and corrective actions; note that units follow their validated limits.
5, 63, 75, minus 18: cold at 5 or below, hot at 63 or above, reheat to 75, freeze at −18. Cool in 2 + 4 hours.