Norovirus has a simple cause: poor hand washing and personal hygiene by food-handling employees. Spread by person-to-person contact, it has created outbreaks on cruise ships and hospitals worldwide.
This food borne illness is easily transmitted when infected food handlers (restaurant or grocery store employees) handle food without properly washing their hands after using the restroom. Norovirus causes vomiting, diarrhea, abdominal pains, and other flu-like symptoms (like achiness and a general feeling of being sick).
Because this virus starts with food service employees not washing their hands, you can get it from almost any food that is already prepared, like salads and sandwiches (food that won’t be washed or cooked before being served to you). Proper cooking can kill this virus, but if the food handler touches the cooked food without washing his/her hands properly after using the restroom, the virus can be back on the cooked food. Bon Appétit!
Should you develop symptoms that last more than a day or so, or you feel really, really sick, seek medical treatment right away. Severe cases have led to dehydration, which worsens the symptoms and slows down recovery.