Proper food storage and preparation can reduce the risk of food poisoning. For example, avoid touching between cooked and uncooked foods, refrigerate foods promptly after purchase or preparation. Washing hands and cleaning surfaces after handling raw meats, poultry, fish, and eggs before touching with other foods, and heating them thoroughly inside is also useful for reducing the risk. To avoid eating raw or undercooked meat, poultry, bivalvia (for example, oyster) is also important for prevention of food poisoning in children. In addition, it is important for medical staff to prevent secondary infection to those who may contact the patients.