<<I have often heard quoted (and read) that when the infant is sensitive to
something in the mother's milk (for example dairy foods) that it can take up
to two weeks on an elimination diet for the substance to clear from the milk
and to see results in the infant.>>
This is in the Breastfeeding Answer Book, pp 100 and 377. Reference is listed
as:
Jakobsson, I. and Lindberg, T. Cow's milk protein causes infant colic in
breastfed infants:  a double blind study.  Pediatrics 1983; 71:268-71.
 It is also referenced as Lawrence's Bfdg: Guide for the Medical Profession,
 4th ed. page 305.

Lisa Jones, LLLL in Wellington FLorida - who was just reading about this
because I am helping a mom w/ four month old, blood in stool and no other
symptoms, mom just reintroduced dairy into her own diet for the first time
since pregnancy, and Ped has mom giving Pedialyte for 24 hours instead of
nursing. AARGH.