Ruth Lawrence (Breastfeeding: A guide for the Medical
Profession, 4th ed.) discusses changes in taste/smell of milk
attributed to increased lipase activity changing the milk fats.
She notes that scalding the fresh milk before freezing halts
this process.

In my practice I have found that sometimes the only change
needed is to switch the storage container. I've had several
cases of off-tasting milk when disposable, inexpensive
(PVC--I think) bags are used. The problem often resolves
when milk is stored in glass, medical grade polypropylene or
the more expensive milk freezing bags (polyethylene interior
with polyester exterior).

I have women try incremental changes: (1) changing the
storage medium (2) make certain milk is insulated from
temperature changes (i.e., stored in rear of freezer, not on
door) (3) scald milk. If one of the early steps solves the
problem one need not proceed down the list.

Of course, sometimes the "mystery" is as simple as asking
what the milk tastes/smells like. If it smells of onions or
garlic or fish one can often trace the onset of "symptoms" to
a recent meal. No need to make any changes as long as
baby is content.

I'm looking forward to hearing your experiences and
solutions.

Margery Wilson, IBCLC
Massachusetts Institute of Technology
Cambridge, Massachusetts, USA
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