I doubt the stringiness means the milk is infected.  But it wouldn't
be so difficult to culture it would it?  I don't think it would be a
big issue to use it.  I would guess the mother had a blocked duct, and
this stringy milk is merely the dehydrated milk that was blocking the
duct.

By the way, ampicillin is not the best drug for treatment of mastitis.

Jack Newman, MD, FRCPC