Plastic milk containers (HDPE #2), Heat, and Leaching

I think it's safe to assume that most or at least many milk containers are heated. In fact, I was told by someone who distributes milk that the way it works generally is that the bottles are formed from plastic pellets that are heated and then blown into a mold to form the actual jug. But one can also buy non-heated containers. So... I know HDPE #2 has been shown to be extremely stable, but I've also heard that when it's heated it can leach? Does anybody know of any research done on this? Just wondering how much it might be leaching... And, no, I'm not saying I think it's dangerous or bad necessarily (I still drink milk). Simply looking for info.

Reply to
xyzer
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You have to melt the polymer to form the container. Browse through FDA extraction requirements here:

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Reply to
Frank Logullo

thanks, i'll check that out... yeah, i guess it makes sense that they have to be melted... So it's a little confusing when I see superior performance claimed by those who say they get HDPE #2 that's never been heated...

For example, at

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They say they use a special non-heated HDPE #2 container and that it makes a difference in leaching.

Reply to
xyzer

Treatment they are talking about would be to adhesion activate the outside of the container. It should do nothing to the inside. FDA reference for food contact approval. I pointed out was that final product must have extractable below a certain level. In order to get FDA food contact approval in the first place, intensive toxicity studies were done on the plastic, its additives and extractible. I would imagine these folks are careful with their milk because food poisoning always comes from the food - not the container. Frank

Reply to
Frank Logullo

This is my guess for the history of two HDPE containers, one used for organicpastures and the other for conventional milk. Both of them were most likely made by injection blow molding, that is, they were both probably made by melting plastic cubes. After making the container, the one for conventional milk container had a surface treatment on the outside of the container to promote label adhesion; the milk is on the inside. The organicpasture container did not have the surface treatment. It is not obvious to me how the surface treatment on the outside of the container induces the migration from the plastic to milk.

It seems to me that you should ask organicpastures to provide date on their claim that there is significantly more migration in the surface treated containers. If they use labels on their containers, you may also want to ask them what adhesive they use to attach the label, and for data on migration from their adhesive to milk.

Ernie

Reply to
Ernie

This is all a lot of rubbish.

If leaching occurs only with heat, than you have nothing to worry about as the milk is always refrigerated. Unfortunately, despite the claims on their webpage, leaching does occur at cold temperatures, albeit at a slower rate. Or is the webpage trying to claim that bottles that are heated post-manufacture undergo some special transistion that only then allows for leaching to occur?

I don't see any position here that they can scientifically defend.

John

Reply to
john.spevacek

Maybe they are sayint that if the HDPE reach Tm, the crystals inside HDPE melts and the diffusion rate of small molecules increases.

I don't think these guys care more about the chemical contamination from bottles than others. What they are doing is nothing different from others.

BTW, can any body imagine a plastic bottle containing a gallon of milk burned, and then we drink the milk from that burned bottle?

Reply to
Xin Zhang

containers

plastic

milk).

I wonder if they are talking about mold release additives that may be in the HDPE. I'm pretty sure milk bottles are made by the blow molding process and it's likely that mold release would be used to speed up the process.

robre

Reply to
robre

I don't think that that's too likely. Mold release is used mininally (it's not cheap), and is not really compatible with the HDPE. (If it was, the first bottle of HDPE would suck all the release off the mold). The mold release would need to diffuse through the entire bottle before reaching the milk, thereby establishing a gradient to further reduce the concentration. Keep in mind that milk has a very short shelf life,

cold storage temperatures all work against there being any significant diffusion.

The proof is in the pudding: as Frank pointed out early last month, there are strong standards regarding leachants.

John

Reply to
john.spevacek

Stearamide is an FDA approved release agent and my even be present in the virgin PE resin. I recall questions on whether or not resin was Kosher as it is OK to use the chemical as long as it is not an animal product. Frank

Reply to
Frank Logullo

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