The Oxford English Dictionary defines "poison" as "a substance that is capable of causing the illness or death of a living organism when introduced or absorbed." The legal definition of the term is "any product or substance that can harm someone if it is used in the wrong way, by the wrong person, or in the wrong amount." The medical condition of poisoning is even broader: It can be caused by substances that are not even legally required to carry the label "poison." Therefore, can food become poisonous? Of course it can if it is infected, tampered with or altered...