Rabbi Falk (From Gateshead) The Posek Hador in worms told us in a shuir that worms are not here to deter us from foods but it is our responsibility to learn how to check each fruit /veg correctly.
I know that Rabbonim around the world have forbidden rasberries as they have been found to be heavily infested and it is almost impossible to clean them as the infestation lives in the flesh.
There is also a huge difference in checking of fruit and veg depending on where you live. E.g strawberries here in England have not been found to be infested.
Incidentally when cooking fish put the fish into boiling water or into hot oil thus any worms will not come out of the flesh.