I see this complaint from moms every so often, too. It seems
that all of us only have the info gleaned from Lawrence's
book, regarding lipase activity and lipid breakdown.

I'd like to appeal to folks with the smarts and necessary
education to help me think about this issue. As you know, I
did some time as a dairy(wo)man. If you have off-flavors in
cows or goats there are in-depth analysis in dairy texts of
why this is.

For instance, in dairy cows, lack of vitamins A & E is said to
increase incidence of mastitis (or sub-clinical mastitis) and is
cause of "cardboardy" or sour tasting milk. (Thus, these
vitamins are given to cows as a supplement when such off
flavors occur).  Acid flavors are said to result from bacterial
growth that occurs when raw milk is not cooled quickly. (The
active bacteria for this is usually Streptococcus lactis.)

There are many definitions of off-flavors in dairy milk. The
flavor described by lipid breakdown is noted in dairy texts as
"a rancid flavor closely associated with bitter flavor; but,
unlike the common bitter flavor, it has an odor resembling
spoiled nutmeats."  There are flavors described as malty,
oxidized, metallic, tallowy, cowy, barny, unclean.

Anyone who wants a crash course can read the materials for
judging dairy products at
www.aac.msstate.edu/pubs/pub1423.htm. The information on
milk is informative.

How much of what goes on in cow's milk might be happening
with human milk? Especially with expressed human milk,
which has only in recent history become popular in such
quantities. With the development of pump technology, and
the sheer numbers of women who avail themselves of this
technology now, I think we need to look at this issue more
critically.

I think that babies are much less critical of flavors than we
humans are when sipping bovine milk; my sense is that bf
babies enjoy the wide range of flavors in their mother's milk.
However, adult humans might be judging human milk by
dairy standards. If the baby refuses the EBM the adults will
be quick to blame the flavor; or wonder if the flavor/aroma
means the milk is rancid. And when/how does it get rancid
when handling seems within normal guidelines? Our
discussions have been narrow in scope compared to those in
dairy circles.

Is there anyone on Lactnet who can address this issue, to
help us identify where we can apply dairy standards to
human EBM?

Margery Wilson, IBCLC