OP - I had this problem and this is what I did -used borax and charlies oxy bleach (or some other "green" powder bleach) and like 3 scoops of mollys suds for babies - which has enzymes that help eat up the milk residue. wash in hot (usually soak for half an hour), the rinse twice. second rinse add 1/4 cup of vinegar.

Don't use green detergent. The scent is there for a reason.

I actualöy have the dame issue with a very good brand new washing machine. I believe the machine does a great job however, baby clothes smell horrid. Baby is on Neocate formula, perhaps thats why it smells? I use to use green laundry detergent and figured I would switch to Tide. Same issue after using Tide original and Tide free & gentle. I also tried adding Borax with no help. I will try vinegar/baking soda tonight... hope it works to get rid of the smell. I also let the clothes dry before putting them into the wash bin to prevent mold or stuff like that. Next is rinsing clothes/bibs and burp blankets prior to letting dry to put in washbin. Weirdly, we use reusable diapers and these come put smelling great!!!

Try a cup of vinegar and a scoop of Oxy Clean.