"David in Normandy" wrote in message
. fr...
Any ideas what cause this? I'm just curious. It doesn't seem to be
directly related to slug damage as the black / grey mass can sometimes be
quite deep inside otherwise apparently pest free potatoes.

I'm curious too! Xmas dins was almost ruined when I discovered that all of
the taters I'd bought from the SM had those black patches in them. I reckon
I wasted 30% of each one. I had intended to steam them unpeeled!! However,
experience has taught me that the spuds available here are not to be
trusted.
I contacted the packer and they promised to send me some sort of recompense,
but it hasn't arrived yet.
Graham