Eight-Hour Cooling in a Café Soup Batch
A 40-seat café cooks tomato and lentil soup in 20-litre batches every Monday. The written HACCP plan says soup must be cooled from 63°C to 10°C within 90 minutes using an ice bath and shallow trays, then stored at 5°C or below for up to three days. On Monday the chef divided a batch into six 10 cm deep trays and placed them in the walk-in at 1 a.m.; the walk-in was already holding four trays of raw chicken on the shelf above. At 9 a.m. Tuesday the probe thermometer recorded 7°C in the soup and 3°C in the air. The chef plans to reheat the soup to 75°C for lunch service and says this makes the cooling failure safe. The café has a blast chiller but it is used for pastries. The manager asks whether the batch can be served and what must change. The café serves 120 covers on weekdays and has a food safety record of two previous cooling deviations.
1. Can the chef make the soup safe by reheating it to 75°C before service? Justify your decision using the recorded times and temperatures.
Read the worked answer
No. Reheating to 75°C kills most vegetative bacteria, but it does not reliably destroy heat-stable toxins or the spores formed during a long cooling period. The soup moved from cooking to 7°C over roughly eight hours, so it spent several hours in the 5–63°C danger zone - far beyond the plan's 90-minute limit to 10°C and its 5°C storage limit. The relevant hazards are toxin-producing spore-formers such as Bacillus cereus and Clostridium perfringens: slow cooling allows spores to germinate and multiply, and the toxin or spore load is not corrected by reheating. The 7°C reading is also above the required storage temperature. Separately, raw chicken was stored on the shelf above the soup, so drip contamination cannot be ruled out. Reheating is a kill step for the intended serving step, not a corrective action that makes a failed cooling batch safe. The batch should be discarded, the discard recorded, and the reason linked to the cooling CCP.
2. Identify the root causes and the corrective actions you would require before the next batch.
Read the worked answer
Root causes include: the blast chiller was not used for the soup; trays were too deep for rapid cooling; the walk-in was overloaded with raw chicken above ready-to-eat food; and no one checked the 90-minute limit. Corrective actions:
- Use the blast chiller or an ice bath with shallow trays (no more than 5 cm deep), and stir to speed cooling.
- Probe the product at the thickest point and record when it reaches 10°C and then 5°C; if the 90-minute limit is missed, discard.
- Store raw chicken below and away from ready-to-eat food, or in a separate unit.
- Schedule soup production so cooling does not coincide with deliveries or pastry use.
- Retrain staff on the cooling CCP and the discard rule, and calibrate the probe thermometer.
- Record the corrective action, the product discarded, and the person responsible. The manager should also review whether the blast chiller capacity is adequate for a 20-litre batch.
3. What verification activities would show the corrected cooling process is under control over the next month?
Read the worked answer
Verification should show the corrected process works repeatedly, not just once. Over the next month:
- Review cooling records daily for the first two weeks, then weekly, checking time to 10°C and final temperature.
- Observe at least three full cooling cycles, including the busiest day, and compare against the plan.
- Confirm the blast chiller is used for soup and that trays are filled to the specified depth.
- Check raw and ready-to-eat storage separation during each walk-in inspection.
- Verify thermometer calibration and keep the certificate.
- Trend cooling deviations at the monthly HACCP review and record any repeat failures as a trigger for a root-cause review.
- Do a challenge run with the largest batch to confirm the 90-minute limit is achievable. If it is not, change the process or the batch size. These activities verify that the control measure is effective and that monitoring is practical.