Any food that is not sterilized and sealed can contain disease-causing bacteria  Once sterilized and properly sealed, however, it contains no bacteria  There are many different acceptable food-preservation techniques; each involves either sterilizing and sealing food or else at least slowing the growth of disease-causing bacteria
Some of the techniques may also destroy natural food enzymes that cause food to spoil or discolor quickly
Any nonsterilized food preserved by an acceptable method can contain disease-causing bacteria.