The art of the gaslight

Annd it's caused by use of contaminated manure (or contaminated runoff water), so buying organic doesn't really help. Buying hydroponic or compost-only (veganic) would, though, but that's probably not available at most supermarkets, and there would be a significant cost premium.

On the other hand, not getting listeria does sound pretty good too.

And of course the problem's source is mass animal agriculture, so stopping eating animals would be a step in the right direction regardless.

You can try to get more of your food directly from the source, and cut out some billionaires (and disease) in the process https://www.eatwild.com/products/index.html