I’m sure it was because of the mayo in the potato salad.
I remember President Eisenhower got sick at some function from something he ate. This was back in the 50s. I am pretty sure it was potato salad.
No. Back before companies had to put dates on cans, I called Hellman's Mayonnaise company to ask about mayonnaise. They said the reason mayo went bad many years ago, was, companies used uncooked eggs. Today, all ingredients are pasteurized. Many people still believe mayo is a killer due to that history, but mayo is safe to be in potato salad and taken on a picnic or at a party or a church social - safe taken anywhere. Treat it as you would treat any fresh food.