Please note that there is currently very high levels of infestation in produce coming from the Yuma, AZ region. The weather there has been unseasonably warm and wet, which is causing very high levels of insect pressure.
Even iceberg lettuce has been found to be heavily infested. We [should] have [currently] stopped certifying much of the iceberg lettuce at Fresh Express and Dole if they are being sourced from [anyplace] Yuma.
The growing season in Yuma ends in the next week or two, [after pesach] at which time we hope the situation will improve as sources move to other regions.[and the mumcham will be able to check properly]
In the meantime, if you buy prewashed lettuce, PLEASE [HAVE AN EXPERT] CHECK BAGS OF LETTUCE CAREFULLY to make sure the STAR-K [OR ANY OTHER CERTIFIER] symbol is present. We are the checking the iceberg daily in various plants and if they bear the STAR-K [OR OTHER CERTIFIER]symbol, they are still certified [BUT REQUIRES EXPERT CHECKING]. However, many bags of iceberg over the next few weeks will NOT bear the STAR-K [OR OTHER CERTIFICATION].
Mashgichim who are [trained experts] checking produce themselves should be extra careful.
NOTE: Any untrained individual including mashgichim, etc should check any vegetables, fruits, etc.
Wishing everyone a Good Shabbos, and a kosher Pesach.