I'm an old guy, and I've seen many examples in the news over the years. I remember a big one from the 80s or 90s when about 9 people from a single family died when the egg salad went bad at a family reunion.

I read that modern commercial mayo isn't what cause the food-poisoning because it tend to contain vinegar and such, but whenever there is an outbreak from a picnic, it's ALWAYS the food with the mayo.

I've read numerous similar stories over the years, did a basic Google search, and got this AI blurb:

Examples of Mayo-Related Food Poisoning Incidents

• Raw Egg Mayo Ban (India): Telangana banned raw egg mayonnaise after over 20 people were hospitalized and one death was reported, linking the cases to contaminated mayo.
• Salmonella in Restaurant Mayo (Saudi Arabia): A restaurant chain’s homemade mayonnaise was linked to an outbreak, with laboratory analysis finding Clostridium botulinum (causing botulism).
• Restaurant Salad Outbreak: A 2000s-era case saw roughly 94 people develop Salmonellosis after consuming salads containing homemade mayonnaise that was left at room temperature for over 3 hours during assembly.
• Club Sandwich Outbreak: An outbreak of Salmonella Typhimurium was traced back to egg mayonnaise sandwiches served at a club canteen.
• Picnic/Buffet Risks: Potato salad, tuna salad, and egg salad left in the sun, where the low acidity of the potatoes or other ingredients allows bacteria to grow rapidly.