Apologies if this has already been posted, but this article is very interesting:
www.theguardian.com/lifeandstyle/2014/may/19/mymilkcount-breastfeeding-mums-milk-isnt-good-enough?CMP=twt_gu
Bounty have been (but are no longer) promoting a service which purports to check the quality of your breastmilk, by testing the levels of DHA, for £99.