I've got this big cheese block, and been eating it over a few days, but its got these little dark specks through it. When i first spotted one i thought it was just a small foreign body that had got in during production so i carried on eating. Thought same thing when i saw another bit yesterday, but felt sick after eating (probably because i was feeling worried about it). Thought I'd try eating it again today, but saw more specks, so left most of it. Feel worried, really can't decide if it is mould! The block is well in date, though it says 'once opened consume within 3 days' and i know its been open at least 5 :-(
Cheese is generally fine for more than 3 days as long as it's kept in the fridge - certainly lasts longer than that in my house or we'd be spending a fortune on cheese! If there's ever any black mould you should throw it away, but blue/green is safe, just chop the affected area off.