The efficiency of microwave ovens in destroying the harmful bacteria frequently found in common foods is diminished by the presence of salt in the food being cooked. When heated in a microwave oven, the interior of unsalted food reaches temperatures high enough to kill bacteria that cause food poisoning, but the interior of salted food does not. Scientists theorize that salt effectively blocks the microwaves from heating the interior.
Which one of the following conclusions is most supported by the information above
A．The kinds of bacteria that cause food poisoning are more likely to be found on the exterior of food than in the interior of food.
B．The incidence of serious food poisoning would be significantly reduced if microwave ovens were not used by consumers to cook or reheat food.
C．The addition of salt to food that has been cooked or reheated in a microwave oven can increase the danger of food poisoning.
D．The danger of food poisoning can be lessened if salt is not used to prepare foods that are to be cooked in a microwave oven.
E．(E) Salt is the primary cause of food poisoning resulting from food that is heated in microwave ovens.