The Almsgiving Curry: Vomiting Three Hours After Lunch

Most likely agent: Staphylococcus aureus - preformed enterotoxin.

• The incubation period rules out infection. Eating at 14:00, vomiting from about 17:00, i.e. roughly 3 hours. Invasive infections such as Salmonella, Campylobacter or E. coli take 12–72 hours and usually bring fever. Toxin-mediated illness strikes in 1–6 hours with little or no fever.
• The food-specific attack rate points at the chicken. Fourteen people who ate the curry became ill; the neighbour who ate only rice and sambol stayed well. The vehicle was in the curry.
• The classic 'rice' answer is excluded on timing, not on reputation. Bacillus cereus emetic syndrome is the reflex answer for rice, but this rice was cooked at 12:30 and 13:30 and served straight from the pot. There was no warm holding period in which spores could germinate and toxin accumulate.
• There is a visible source. A discharging sore on a handler's finger plus bare-hand contact with cooked food is the textbook route: S. aureus lives in skin lesions and the nose, and multiplies to toxin-producing numbers in a few hours at 30 °C.
• Diarrhoea-dominant agents do not fit. Clostridium perfringens gives cramps and diarrhoea at 8–12 hours, not vomiting at 3 hours.

Laboratory confirmation (vomit, stool and food samples via the MOH) should still be requested, but the epidemiological pattern is strong enough to justify control action immediately.

The argument fails because the cooking step came before the contamination step, not after it.

1. Boiling at 08:00 did destroy vegetative bacteria in the raw chicken - that is why the food was safe at that moment.
2. Between 08:00 and 08:30 the cooked chicken was recontaminated by bare-hand mixing. The handler's finger had a discharging lesion, an abundant source of S. aureus, and the plaster lost in the pot only added to it.
3. The curry was then held at about 30 °C for six hours - squarely in the danger zone and close to the optimum for staphylococcal growth. Numbers climb from a few cells to millions per gram in that window.
4. S. aureus enterotoxin is heat-stable. Once formed in the food, reheating or boiling does not reliably destroy it, so the 14:00 service delivered preformed toxin directly.

So the correct statement is not 'cooking kills everything' but 'cooking only protects what happens after cooking'. Any heat treatment can be undone by recontamination plus time in the danger zone - which is exactly the combination that occurred.

Immediate (0–24 hours)

• Stop serving and retain the remaining curry, unaltered and labelled, in case the PHI or MOH wants samples; do not discard or 'clean up' before the inspection.
• Advise affected guests to seek medical care and report the incident to the area MOH/PHI so that food poisoning is investigated and notified properly.
• Take the handler off all food work until the finger lesion is assessed and can be covered with a waterproof dressing; she should not handle ready-to-eat food at all while it discharges.
• Discard any food she touched after cooking; clean and sanitise all work surfaces, pots and cloths.

Longer term

• No bare-hand contact with cooked or ready-to-eat food - use spoons, tongs or clean gloves, and wash hands at a proper basin before and after.
• Time control: cooked food either served within 2 hours, held at 60 °C or above, or cooled rapidly to 5 °C or below.
• Daily health check of handlers for skin lesions, diarrhoea and vomiting, with a nominated person to report to.
• Written hygiene instructions and training, and registration of the food business with the local authority if food is sold rather than only served free of charge.

The investment is small compared with the cost of a repeat outbreak and the enforcement action that would follow.