A foodborne outbreak at a wedding reception

Incubation pattern. Most cases at 28–36 hours is consistent with Clostridium perfringens (typically 8–16 h, but can be longer) or Bacillus cereus (emetic type 1–6 h; diarrhoeal type 8–16 h). The small group with onset at 6–8 hours who ate only the vegetarian option suggests a short-incubation agent - likely B. cereus (emetic toxin from rice) or Staphylococcus aureus toxin (1–6 h).

Vehicle hypotheses.

• Cold rice salad - classic B. cereus emetic syndrome if cooked rice is cooled slowly and left at room temperature. This fits the 6–8 h vegetarian cases.
• Chicken liver pâté / turkey - Campylobacter (2–5 days, too long for most here), Salmonella (6–72 h), C. perfringens (from reheated meat).
• Cheesecake - S. aureus toxin if handled and left warm.

Most likely. A mixed picture: B. cereus from rice for the early cases, and C. perfringens or Salmonella for the 28–36 h cases. Do not assume a single agent.

Key judgement. The incubation period is the strongest clue. Anchor on it, but keep the differential open until cultures return.

Immediate measures.

1. Exclude the caterer from food handling pending investigation - this is precautionary and proportionate given a domestic kitchen, overnight storage, and vulnerable nursery customers.
2. Notify the nursery and advise them to discard any food supplied by this caterer; monitor children and staff for symptoms; exclude symptomatic individuals per national guidance (typically 48 hours symptom-free).
3. Obtain food and clinical samples - leftover food if available, stool cultures from cases, and food-handler stool samples. Early sampling is time-critical.
4. Interview cases with a structured questionnaire (food history, timing) to confirm the vehicle.
5. Advise cases on hygiene and exclusion (48 hours symptom-free for most; longer for certain agents).
6. Inspect the caterer's premises and review food safety management.

Justification before results. You do not need microbiological confirmation to act when there is a plausible common exposure, a consistent incubation period, and a vulnerable population (nursery children). The precautionary principle applies: the cost of excluding the caterer temporarily is low; the cost of a nursery outbreak is high.

Proportionality. Do not close the nursery or issue mass alerts without evidence; target action at the implicated food and handler.

Approach.

• Communicate the rationale in writing: the exclusion is precautionary, time-limited, and reviewable; it is not an accusation.
• Set a review date (e.g. 48–72 hours, or on receipt of negative results) so the exclusion is not open-ended.
• Offer a route to return: negative stool samples and evidence of safe practice can support lifting the exclusion.
• Document everything - the risk assessment, the decision-maker, and the review.

Statutory powers (England, illustrative). Under the Public Health (Control of Disease) Act 1984 and the Health Protection (Notification) Regulations 2010, certain foodborne infections are notifiable. Local authorities have powers under food safety legislation (Food Safety Act 1990; Food Hygiene Regulations) to restrict a food business, serve improvement/hygiene emergency prohibition notices, or close premises where there is an imminent risk to health. A Hygiene Emergency Prohibition Notice requires a formal risk assessment and can be appealed.

Judgement. Prefer voluntary cooperation and negotiation first; use statutory powers only where voluntary measures fail or risk is imminent. Keep the tone collaborative - the goal is protecting the public, not punishing the caterer.