Occasional cases of cholera occurred in Hong Kong in the past few years with seven cases reported in 2008. Cholera is caused by Vibrio cholerae. Hot weather of the summer season is favourable to the growth of pathogens. We must therefore be particularly vigilant on the food safety measures.

Cholera is a foodborne illness with symptoms like severe diarrhea, vomiting and dehydration and can lead to death in severe cases. As Vibrio cholerae is naturally present in seawater, seafood may easily be contaminated. Hence, you should observe the Five Keys to Food Safety when you prepare food, in particular seafood, to prevent from getting cholera.

First, choose. Purchase raw materials and ingredients from hygienic and reliable shops and choose seafood, like shellfish that are fresh, with intact shell and free from abnormal odour. Do not buy food from illegal hawkers or suspicious sources, such as food sold at unreasonably low price or with unnatural colour.

Second, clean. Wash hands thoroughly before and after handling food. Clean cutting boards, knives, other utensils, washbasin and work surfaces with hot water and detergent upon handling food. Seafood, especially crustaceans and bivalve shellfish, should be washed thoroughly. Handle waste removed from seafood carefully to avoid contaminating other foods and utensils.

Third, separate. After purchase, raw seafood should be separated from other food items to prevent their juices from contaminating other food items. Use covered container to hold food and store it carefully in the refrigerator. Cooked and ready-to-eat foods should be put on the upper compartment, while raw seafood placed on the lower compartment so as to prevent contamination of cooked food by juices dripping from raw seafood. Use different sets of utensils and cutting boards to handle raw and cooked foods separately.

Fourth, cook. The most important key to cholera prevention is to cook food thoroughly. Cook shellfish until the shell is open and then further cook for three to five minutes. Shellfish without shell should be cooked for three minutes after the water boils.

Lastly, safe temperature. Cold dishes should be kept at 4℃ or below. Cooked food should be consumed immediately and do not keep food at room temperature for more than two hours. Refrigerate leftovers at 4℃ or below and reheat them thoroughly before eating.

Seafood is a popular food item. To enjoy it safely, always follow the Five Keys during preparation and cooking.