Sure, but that isn't the prime vector of E Coli and other illnesses spreading. E Coli literally comes from workers shitting in the fields due to the breakdown of the labor movement, as they are not allowed breaks or access to a bathroom with a place to wash afterwards. Thus how you end up with Chipotle serving up E Coli covered veggies.

Not having a store that your food comes from might make for a safer mental picture, but Amazon is going to go with the cheapest vendor every time, and they don't have the scale of Kroger or HEB to knock prices down anywhere near them, thus they must buy lower quality goods to hit the same price point.