Brown rot

Mac95

Hi,
A few of the pears and apples growing in my garden have rotted while on the tree. We usually get a few each year and it's not been a major issue.
Today, however, one of the pears I picked last week - which was rock hard and looked perfectly healthy at the time - had rot on it.
I'm now concerned that other healthy-looking fruit are actually infected but won't show signs before they've been pressed.
What's the best thing to do? I've picked a couple dozen pears already and are letting them soften in a sealed container for a few days to soften. I'm also not sure if campden tablets can kill fungi.
I'm going to check the picked fruit for signs of damage which would let fungi in.
Cheers!
M