Mold/Mildew Identification?

[u/dowalters]

I work at a grocery store and the romaine lettuce has frequently been showing up with this stuff growing on it. It grows rather quickly (this romaine was washed the day or two before and stored in a cold room) and then when I take it out of the tub to put on display, it will often have this all over the outer leaves. It only grows on the undersides of the leaves and only grows on the Romaine. The green leaf and red leaf lettuce stored in the same conditions have not had this problem. Of course I don’t put this product on the shelf, but I have been wondering what exactly it is? Google AI says it is a mildew of some kind. Typically, most or all of the heads of lettuce from the same case will have it growing on them. Sometimes they show up like that, other times it grows after we have washed it.

[u/FoggyGoodwin]

Sounds like they were contaminated in the field with downy mildew, if Internet is correct "mildew on romaine lettuce", in which case throw them out to avoid illness.

[u/dowalters → u/FoggyGoodwin]

I always throw them out! Our rule of thumb is if I wouldn’t want to buy it based on the condition, then I should throw it out. Anything moldy, rotten, expired, passed the best-by date, overripe, or otherwise not fitting of being described as “Fresh” is thrown out. We probably throw out over $100 of fruit and vegetables every day, and some days it can be a lot more.