It is useless to become paranoid about listeria and cantaloupe, but it does point out how "little" or "minor" things can easily become significant. If the "right" (i.e., "wrong") person is exposed to something that may not hurt most people, it can be toxic and even deadly. If one is "careless" about how they handle even the seemingly routine things, he or she can have a devastating impact. Even without evil intentions, harm is done!
Perhaps the most common way we contaminate and poison others is through our words. On the surface, they are seemingly insignificant. But they can quickly injure or contribute to the spiritual death of the weak, vulnerable, and otherwise susceptible. James warns of the volatile potential of the tongue (Js. 3:2ff). Proverbs 18:21 says, "Death and life are in the power of the tongue."
We also must watch our example. Others are watching how we react to life, they see our attitudes, and they examine our choices. We may brush something off as "no big deal," but it might be deadly for them. Jesus warns, "It is inevitable that stumbling blocks come, but woe to him through whom they come! It would be better for him if a millstone were hung around his neck and he were thrown into the sea, than that he would cause one of these little ones to stumble" (Lk. 17:1-2).
May our lives bring spiritual health and life to others! May we disdain what is otherwise! Eternal lives are at stake.