[myself248]

If the grocery store signs up with a new lettuce distributor, whose FDA paperwork is covered in Wite-Out but nobody at the store calls the FDA to see if it's legit, and who seems to have only been in the lettuce business for two weeks, and whose trucks are freshly painted, and whose proprietor looks a lot like the proprietor of a recently-disgraced lettuce distributor who was in trouble for peddling contaminated lettuce but THIS GUY wears a DIFFERENT HAT so it's definitely not him...

Then yes, the grocery store absolutely has been negligent.

As a consumer, it is not within my capability to find and verify the bona fides of the distributor. That information stops at the grocery store's back room. It is incumbent on the grocery store to do at least the most basic checks and act on them. I as the consumer am not buying lettuce from the distributor in the back room, I am buying it from the grocery store at the checkout lane up front.

Acting like nobody knew it was possible to get sick from dodgy lettuce, or like there was a whole health-and-safety regime to try to prevent that, and failing to diligently confirm that this distributor's safety certs were authentic, is the DEFINITION of negligence.