If cheese is practically mouldy milk how come we don’t eat mouldy cheese?

Question: If cheese is practically mouldy milk how come we don't eat mouldy cheese?
- Keywords:
  cheese,
  food,
  milk
Asked by harperstuff to Asif, Laura, Lena, Sean, Viv on 14 Mar 2012.
- Laura Waters answered on 14 Mar 2012:
  
  We do! Some people love blue cheese (not me, yuck!). However, it is grown under controlled conditions to get the right kind of mould to grow.
- Lena Ciric answered on 14 Mar 2012:
  
  Yep. Laura is right. We actually use all sort of different microbes in cheese production. Lactobacilli and streptococci convert the milk sugar (lactose) to lactic acid and make the cheese acidic which makes it inhospitable to other microbes that might spoil it. Most of these bugs die off in the cheese-making process but some are used to flavour cheeses like emmental, gruyere and pecorino.
  
  The mould that you see in blue cheese like (stilton, roquefort and gorgonzola) belongs to the penicillin family.
  
  There is even a Sardinian cheese called case marzu that contains live maggots. Eek!

Question: If cheese is practically mouldy milk how come we don't eat mouldy cheese?