For 50 years I have credited my Mom’s olfactory alarm system for saving us from one of the deadliest poisons known to man. She religiously poked her nose into every can before ruling it fit for consumption. But my memory hasn’t kept up with that of my 97-year-old mother. She remembers that she rejected the Tainted Tuna because of how it looked. I was 13 at the time, and eager to make Mom’s sweet and crunchy tuna salad, a task I always relished (pun unavoidable). I opened the only can we had on the shelf and handed it to Mom. She took a whiff. Fine. But then she stopped. “It looked nasty,” she says.…