Dear Rose,

I recently attended a conference where Lois Arnold (US National Commission
on Donar Milk Banking) talked about the container issue for human milk. Her
message about the single use plastic bags was that:
1. There is a greater contamination issue during there use - due to the fact
that they are difficult to use, do not support themselves and thus give a
higher chance of contamination, difficult to seal,
2. She also showed a slide of how they can split during freezing and thus
contaminate other bags they are stored with (aside from loosing a whole lot
of precious milk),
3. Loss of milk components - fat SIgA specific for E.coli polysaccharides
(Goldburn et al 1981; Hamosh 1994)
4. Cost - single use.
5. potential for oxidation of components (not air tight)
6. potential for photodegradation of components (just like any clear
container I guess)
It was quite clear from her talk that she was no fan of their use in the
NICU.

This is what she showed from references mentioned:
The Goldblum reference - sIgA antibodies specific to E.coli polysaccharides
decrease by 60% in polyethylene (the bags are soft plastic i.e.
polyethylene). Concentration remains the same in glass and polypropylene
(i.e. hard plastic).

The Hamosh study (1994) - lipids adhere to walls of polyethylene bags & loss
of fat soluble vitamins with fat loss.

Also, if your going to research this area further, she gave a good tip that
when checking studies on milk storage and containers to look at how long
after storage different milk components were assayed - eg. some studies
looked at leukocytes within four hours in glass containers and found that
the leuk. count was lower in glass containers. However, another study look
over a period of 24 hours and found the leuk. count to be the same. Ok, I'm
rambling on about something most will know about.

Here are the refs. she talked about regarding plastic bags:
Goldblum et al
Human Milk Banking. I. Effects of container upon immunological factors in
mature milk
Nutr. Res. 1:449-459, 1981
Hamosh M
Breastmilk Storage: Review of the literature and recommendations for
research needs.
Wellstart International: San Diego 31pp., 1994

plus:
Arnold LDW, ed: Recommendations for collection, Storage and Handling of a
Mother;s Milk for her own infant in the Hospital Setting. HMBANA: Denver,
CO. 24pp., 1999.

Hope this helps?

Sara Bernard
(ps. I have one of those bags with my own milk in the deep-freeze at home -
it's now at least 2 years old and can't bear to throw it away!)

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