The Funeral Catering
At a funeral in Cape Coast, a caterer cooks 40 kg of rice and 30 litres of groundnut stew at 6 a.m. in a home kitchen. The food is poured into six large plastic buckets, covered with cloth, and transported in the back of a pickup for 40 minutes in 31°C heat. It arrives at the funeral ground at 9 a.m. and is placed on tables in the shade. Serving begins at 1 p.m. and continues until 3 p.m.; six volunteers serve with their hands, using one serving spoon rinsed in a bucket of water between dishes. About 200 guests eat. Between 6 p.m. and 9 p.m., 28 guests develop nausea and vomiting, some with diarrhoea; none has fever. Two guests who arrived late and ate only rice and stew from the last bucket are also ill. The caterer says the stew was “still hot” at 1 p.m. and blames the rice.
1. What is the most likely hazard, and what is the evidence? Consider at least two competing explanations and say how you would discriminate between them.
Read the worked answer
Most likely hazard: a pre-formed bacterial toxin. The two strongest candidates are Bacillus cereus emetic toxin from cooked rice held warm for hours, and Staphylococcus aureus toxin from hand contact followed by long holding. Both fit the short incubation period: the guests ate between 1 p.m. and 3 p.m. and became ill between 6 p.m. and 9 p.m., roughly 3–8 hours later, with vomiting predominating and no fever.
The “still hot” claim is unreliable. A large bucket can feel hot at the edge while the centre sits in the danger zone. The cloth covers do not control temperature. The single spoon rinsed in a shared bucket is a cross-contamination route.
Competing explanations
- Contaminated water used for cooking or rinsing utensils - possible, but would be expected to affect stew and rice equally and perhaps cause more diarrhoea.
- A food handler carrying S. aureus or norovirus - possible, especially with bare-hand serving; norovirus usually has a longer incubation (12–48 hours), which fits less well.
- Rice cooked the previous day and inadequately cooled - possible; the caterer's timeline should be checked.
How to discriminate
- Calculate attack rates by food item (rice only, stew only, both).
- Interview the two late guests in detail: illness after eating from the last bucket fits prolonged holding rather than a single early contamination event.
- Sample remaining rice, stew, rinsing water and utensils.
- Collect stool and vomit samples from cases and nasal/hand swabs from handlers.
- Review cooking and holding times with the caterer.
2. Identify the critical control failures from cooking to service, and the corrective action for each.
Read the worked answer
1. Cooking and holding without temperature control. Forty kilograms of rice and 30 litres of stew cannot be kept safely in unmonitored buckets. Corrective action: cook as close to service as possible, or rapidly cool and later reheat to at least 74°C; hold hot food at 60°C or above using insulated containers or a hot box; use a probe thermometer and log temperatures.
2. Unsafe transport. Open buckets covered with cloth in a pickup expose food to dust, insects and vehicle exhaust, and provide no insulation. Corrective action: use clean, lidded, food-grade insulated containers and transport separately from other loads.
3. Ambient holding from 9 a.m. to 3 p.m. At 31°C, this is ideal for toxin production. Corrective action: reduce the holding window, hold hot or cool rapidly, and discard food that has exceeded the time limit.
4. Bare-hand serving and a single rinsing bucket. Corrective action: provide handwashing with soap and running water or an alcohol-based sanitiser, use clean utensils for each dish, and replace rinsing water frequently or use disposable gloves with proper hand hygiene.
5. No supervisor, thermometer or records. Corrective action: assign a trained person to monitor time and temperature, keep a simple log, and give that person authority to stop service.
3. What should the caterer and the environmental health officer do now?
Read the worked answer
Caterer
- Stop serving immediately and retain all remaining food, utensils and buckets for sampling. Refrigerate samples if possible; do not discard them until authorised.
- List the menu, suppliers, cooking times, staff and volunteers.
- Send any symptomatic staff home and to a clinic; exclude them from food work until cleared.
- Cooperate fully with the EHO and provide a factual account. Do not speculate publicly about the rice or blame guests.
- Clean and disinfect the kitchen and equipment after sampling.
- Do not cater again until the kitchen, water supply and staff health are verified.
Environmental health officer
- Interview cases and a sample of well guests to calculate attack rates.
- Collect food, water, utensil and environmental samples, and arrange clinical sampling.
- Inspect the home kitchen for water source, handwashing, refrigeration and pest control.
- Check the health status of handlers and exclude anyone with symptoms.
- Advise the family and provide factual public health guidance without naming individuals unnecessarily.
Reasoning. The priority is to stop further exposure and preserve evidence. The pattern already suggests a toxin produced during prolonged warm holding, so the investigation should focus on time-temperature history and hand hygiene rather than on the stew alone.