Mites and diatomaceous earth

[nickjonespmcd1]

I look after the cheese store at Plaw Hatch Farm, Sussex, UK.  Our store is bursting at the seams currently and I have been finding the cheese turning and vacuuming exhausting so I'm looking for other means of keeping control of mites.  I've read a lot of references to diatomaceous earth (which we already have for other purposes) - but I can't find any reference on how to use it.
Should I rub it in to the cheese? Sprinkle it over the shelves? I will check if the stuff we have is food grade.

Also - any opinions on pyrethrin (is it actually non toxic), or Mary Quicke's contraption?

Thanks for any replies.