Medicine: Canned Death

For the vacationing Nelson family from Kansas City, it was a festive family dinner down on the farm—Grandpa Aaron Gruwell's farm at Idaho Falls, Idaho. Kenneth Nelson, 45, a mechanic, and his wife Naomi had driven west with their five children, aged 4 to 15. Grandma Gruwell always set a good table. This time she served home-canned beets, but explained at the dining table: "I didn't can these myself. I got them from a friend, and they taste to me like they need a bit more vinegar."

Last week, because of the beets, Aaron Gruwell...