What I've heard (and I'm only citing unverified word of mouth) is that E.Coli is within the leaf itself, it comes from the water it used. You cannot wash it off or clean it. An infected head of lettuce is garbage.
As to those wondering why this is significant:
- Eating burgers and fries that turn out to be poison... "told you so"
- Eating salad and veggies that turn out to be poison... wtf.
A silly comparison, but it does raise the concern that even those that watch what they eat and try to be healthy can't escape the widespread bacterial problems in food in modern industrial food processing.
Does dumping it into a colander, and running water across it not count?
(Essentially, the same way one would wash fruit such as blueberries or strawberries, though I usually use the box those come in since they already have holes.)
Some pathogens can't be washed off. Others can if you scrub, but not if you rinse.
If you buy the whole head, pathogens can hide in the core. And if you buy pre-cut bagged salad, how can you wash that?
What if you drench the salad in vinegar before eating it, will that kill E. coli O157:H7?