Do plastic milk bags have less vitamins than paper carton milk containers? I read health news report on Canadian CBC web site which indicated the florescent lamps from grocery store emit UV rays which break down the vitamins in plastic milk bags.

I want to confirm the fact with you guys on this forum. I can't find info elsewhere.

Based upon my experience with the use of UV in the lab, I do not think you have anything of which to be concerned. Back in the 50s, 60s and early 70s, UV lights were commonly set up in many labs for pass through areas; doorways, change rooms, pass-through boxes, etc. to control/reduce bacterial contamination. It was found that even a thin layer of dust on the bulb’s surface reduced the efficacy significantly to eventually warrant the elimination of these devices in most areas. Directional airflow; positive air pressure and air showers were found more effective.

Even if there were some penetration of the UV through the plastic, only the milk along the surface where the UV light hits would be exposed.

Pete

what? why don't you drink milk anymore? Izzy. Our bodies lose calcium as we age.

Yes, exposure to light does break down Vitamin A. In addition, UV light can cause oxidation of fat causing slight changes in the flavor of milk.

A study done at Cornell University (L.J. Whited, et. al. 2002, Journal of Dairy Science, Vol. 85, Pages 351-354) showed a 32% reduction in Vitamin A in skim milk (in clear gallon containers) after 16 hours of exposure to florescent light of an intensity similar to grocery store lighting (1000 lx). Reduced fat milk showed a reduction of 24% and whole milk did not change. Brighter light and longer exposure times result in greater reductions in Vitamin A.

Vitamin A is a fat soluble vitamin and it seems that milk fat protects the vitamin from breakdown which is why there is more reduction in Vit. A in Skim milk than whole.

Trained tasters were able to detect an off flavor from light oxidation of fats in whole milk after 4 hours of exposure to light. It took longer to develop off flavors in skim milk (less fat to oxidize). Note these were trained milk taster, most people probably would'nt notice.

The old paperboard milk containers provide protection from light. More of the milk processors are moving to colored gallon jugs or to including a UV blocker in in the polyethylene jugs.

So, if you want the absolute best, buy your milk in opaque containers. Or, do what I do, don't worry about it and buy whatever is on sale.