My wife was told by a friend that a certain legitimate kashrus organization says that frozen raspberries do not require supervision, and upon calling the organization, she was told that the process the berries go through before freezing removes all insects. Does anyone know what this process is and what the general opinion in the kashrus world is about such things?
The CRC says in a tweet:
[T]he way the berries are processed is sufficient to clean them, as opposed to other frozen products
The CRC generally states the things that a consensus position between themselves, the OK, the OU, the Kof-K and the Star-K (there may be outliers among that group for any given position, but most of them will agree to the position, or at least accept products from each other that conform to that position). However the OK's Vegetable Checking Guide only permits frozen raspberries if they are pureed by the user after a cursory check (described there).
This volume of Halachically speaking agrees with the OK (that raspberries need to be purred to be used) and provides reasoning for it. From the reasoning described there, the process involved is a government required washing. It depends on if, immediately prior to the freezing, after the government required washing, the bugs were a Miyut HaMatzui - a commonly found minority, or if they were Eino Matzui - not commonly found. Halachically speaking agrees about strawberries, for example, that the washing is sufficient, but regarding raspberries it says the washing is insufficient to remove it from that category.
It would seem that the CRC position is about how effective the washing prior to freezing is at removing bugs, and they think it is sufficient.
I'm not sure why freezing fruit would cause insects to disintegrate. The fruit is flash frozen to prevent the cell walls bursting which should similarly preserve the insects.
Some frozen fruit and vegetables are pressure sprayed to remove insects. For example although thrips are commonly found between maize kernels on the cob, most poskim permit frozen corn due to pressure spraying.
The pressure that can be used depends on how hard the fruit or vegetable is, though. With lower pressure spraying you reduce the probability of eliminating all insects, but it could become a miut she'eino matzuy.