Walk-in Failure Mid-Service: What Leaves the Kitchen?
At 16:40 on a Friday, with 180 covers booked for 19:00, the chef checks the main walk-in. The air probe reads 9.2 °C; the 08:00 log entry was 3.1 °C. The door was left ajar after a 13:30 delivery and nobody noticed. Product temperatures: cooked, sliced chicken thighs cooled the previous night for the Caesar salad, 11 °C; whole raw lamb shoulders, 8 °C; vacuum-packed smoked salmon sides, 6 °C; and a 20 L pot of veal stock taken off the stove at 13:00 and left on the bench to cool, now reading 32 °C. At 15:00 a supplier delivered 15 kg of frozen prawns; a probe between two blocks read −8 °C, and the driver says the lorry freezer has been running a bit warm since Nicosia. The kitchen has one under-counter fridge at 4 °C with about 40 L free, an empty blast chiller, and no spare stock of anything.
1. Decide the disposition of each of the five items (chicken, lamb, salmon, stock, prawns). For each, state keep / discard / reject and the reasoning you would put in writing if an inspector asked.
Read the worked answer
Work item by item, and record the reasoning, because the decision is only defensible if the evidence is written down.
- Cooked chicken thighs, 11 °C - discard. This is a ready-to-eat food, so no kill step remains. It has been above 5 °C for an unknown period, possibly since before 13:30. Reheating to 75 °C would kill vegetative cells but not heat-stable toxins such as Bacillus cereus cereulide or staphylococcal enterotoxin, and any Listeria that has multiplied is still a problem in a cold-plated salad.
- Raw lamb shoulders, 8 °C - conditional. Raw meat that will be cooked through is lower risk, but the time out of temperature is unknown. Accept only if the log and door records show an excursion of under two hours; then cook it today to at least 75 °C throughout and do not cool and reheat it. Otherwise discard and document.
- Smoked salmon sides, 6 °C - discard. Ready-to-eat, vacuum-packed and temperature-abused is the textbook Listeria scenario. The anaerobic pack does not help; it protects the organism.
- Veal stock, 32 °C after roughly 3.5 hours on the bench - discard. It has sat in the danger zone and a 20 L pot cannot now be cooled inside the roughly 90-minute benchmark from 63 °C to 10 °C. The failure has already happened.
- Frozen prawns at −8 °C - reject at the door. Frozen storage requires −18 °C or colder. −8 °C means partial thaw with unknown duration and ice-crystal damage. Do not sign for them; record the rejection on the delivery note.
Rule applied throughout: if you cannot show the time, you cannot keep the food.
2. It is 16:50. Set out the corrective-action sequence for the next 90 minutes: the fridge, the rejected delivery and the evening menu.
Read the worked answer
Sequence by risk, not by convenience.
- Contain. Close the walk-in, stop all traffic into it, and move only the items you have justified keeping (here: nothing except possibly the lamb, if the evidence supports it) into the working 4 °C fridge or the blast chiller. Do not stack warm product against cold.
- Record. Fill in the HACCP corrective-action form: air and product temperatures, times, the ajar door, the decision and the name of the person deciding. Photograph the probe readings. This is the document that protects the business.
- Engineer. Call refrigeration service immediately; until it is repaired, treat the walk-in as out of service and tag it. Check whether the door alarm or a self-closing hinge is missing, and add a mid-service temperature check to the daily sheet, because the 08:00 reading clearly is not enough.
- Delivery. Reject the prawns formally, get the rejection acknowledged, and tell the supplier that no further frozen deliveries will be accepted without a temperature record from the lorry.
- Menu. Rewrite the evening on what is safe and available, not on what was planned: pull the Caesar salad and the smoked salmon starter, and replace them with dishes built from verified stock or from a fast emergency purchase. Reducing choice is better than serving a risk. Tell the front of house before service, give them the words to say, and log the substitutions.
- Root cause for next week. Stocks must be decanted into shallow gastronorms and cooled in the blast chiller, never left in the stockpot.
3. The head chef says: just reheat the chicken to 75 °C and it will be fine. Explain in two or three sentences why that does not solve the problem, and what the underlying principle is.
Read the worked answer
Reheating kills live bacteria but does nothing to toxins they have already produced. Bacillus cereus cereulide and staphylococcal enterotoxin are heat-stable and survive boiling, and Listeria that has grown in a cold-plated salad is not addressed by reheating a product that will be served cold anyway. The principle is that heat treatment is a control for vegetative pathogens, not a repair for time-temperature abuse: you manage the hazard by controlling time in the danger zone, and once that control has been lost you cannot buy it back with a probe.