When food smells or tastes bad, you know that spoilage has occurred, but some spoiled foods will have no changes in taste, appearance, or odor. These are the ones that are dangerous. They, too, can cause food poisoning.
Food borne illness is fairly common in the United States.
It is caused by toxins. Don't touch your face, mouth, nose, or hair when preparing or serving food. If hot foods aren't to be eaten as soon as they're cooked, refrigerate them, then reheat them before they're served. Always refrigerate cream pies, custards puddings, creamed meat dishes, sandwich fillings with mayonnaise, and potato salad. Do so promptly after preparing.