The cluster involved four males and six females, aged 25 to 44.

Raw oysters

• Consumption of raw or undercooked food
• Food suspected to be contaminated with norovirus

• Raw oysters are high-risk food, as there is no heat treatment to kill foodborne pathogens or antimicrobial-resistant bacteria before eating.

• Purchase oysters intended for raw consumption (either live inshell oysters or frozen oysters) from reputable and hygienic suppliers. Maintain a purchase log and look out for the condition and expiry date for prepackaged products.

• Ensure that staff maintain good personal hygiene and wash hands thoroughly between handling raw oysters and other foods. Utensils, equipment and working area are cleaned and disinfected regularly as needed.

• Use clean and sterile towels for oysters. Use only designated tools and equipment for handling them separately. The equipment should be labelled “oysters eaten raw only”, and kept separately from other equipment.

• Raw oysters should be stored in a designated refrigerator to avoid cross-contamination with other foods.

• Oysters from the same batch and source should be put into the same container, they should be used on a first-in, first-out basis.

• Keep oysters between 2°C and 4°C for at most two days. If keeping the oysters for longer than two days is expected, freeze them. Defrost oysters and other foods in a designated refrigerator and separate them from other food items.

• Oyster handlings when occurring at room temperature, should not exceed one hour.

• Display live oysters on crushed edible ice, replace ice in a timely manner and drain melted ice-water as needed.

• It is necessary to strengthen the training on food safety, environment and personal hygiene of management personnel and food handlers.