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What's in my milk carton? the dreaded wet-strength...

I'd never thought much about buying milk cartons in paper containers before taking the Master Recycler class. When they were empty, I'd rinse them out, remove the plastic pouring spouts, then crush and place them in my recycle bin. Turns out they're not very recyclable.

Ever heard of wet-strength? It is not a super-hero power. It is a synthetic material injected into paper to make it stand up to moisture. Makes sense when you think about it. Why else would paper (which usually disintegrates when wet) hold a gallon of milk, or 16 oz. of soup (as in those brick packs or aseptic boxes)? The brick packs are perhaps a shade worse, as they are made from plastic-coated paper with aluminum foil backing and crimped metal ends. Taken alone, plastic, paper, aluminum and metal are recyclable. Combined to make these fancy composite-material packages... not so recyclable any more. Mixed materials packages are hard to separate, and typically end up downcycled. If you're wondering, downcycling is a step below recycling. It can be used again, but is re-made into a material of lesser quality. With paper containing wet strength, it gets downcycled into tissue paper (on the flipside, regular paper fibers can usually be recycled about 7 times before the fibers get too short and no longer usable).

The thing about wet strength is that you really have no way of knowing it's there. Cardboard that looks like regular cardboard typically has wet strength in it if it's intended for freezer packaging or holding liquids (like the milk and juice cartons, called "gabled boxes"). The chemical resins used in wet strength are fairly nasty sounding:

Not really something I want sitting right next to my food. I know several people who won't buy milk in a plastic container, because they don't want plastic touching their food. So be aware that this wet-strength injected paper packaging may not be necessarily better.

If this is something you're passionate about, food manufacturers need to know what you think. Use their 800-numbers and tell them. Write them a letter. If enough of us do, perhaps they'll make some changes. Or do some more reading on the subject:  Cradle to Cradle: Remaking the Way we Make Things by William McDonough and Michael Braungart.


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