Isn’t it also the case that a lot of these contaminations in produce (like leafy greens) are caused by animal manure being used to fertilize the produce?

Without manure being used the risk is diminished by orders of magnitude.

Only little backyard operations use animal manure. No large food chain will carry greens grown in animal manure.

Maybe so, but how does that explain how E. coli outbreaks on lettuce? From what I understand the waste from animal farms run off into waterways that feed the vegetable farms.

Looking into this, it's hard to say since there are contamination issues at every point between preharvest and the moment you put it into your mouth: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6899298/

It doesn't seem to rank the causes it lists, but googling it suggests widespread contamination caused by fecal matter runoff from animal ag finding its way into irrigation water.

Field workers who don't get bathroom breaks.

Rabbits? It's not exactly easy ensure there are no animals across thousands of square miles of farmland.

Here in Canada we have pretty heavy application of manure, primarily in spring and fall. It's part of how we replenish soils at small and large scales.

I suspect we rarely grow greens immediately after applications, but to say only backyard operations use animal manure isn't true.

Evidently this is a common and well-researched practice in the USA as well: https://www.researchgate.net/publication/286297896_Animal_Ma...

Have you heard of a small movement called organic farming? https://external-content.duckduckgo.com/iu/?u=https%3A%2F%2F...

From that link it looks like about half of illnesses are from animal products and half is from produce. Deaths from animal products is higher.

The data is also from 2008. Things have likely changed since US households and food prep has been heavily focused on cleanliness around animal products but nowhere near as much focus is on produce. The 'pre-washed' pre-packaged produce is especially risky.