I’d been a raw milk drinker for years. Yet I hadn’t expected to respond so negatively to the glass of Horizon organic milk my friend poured for me. After all, that’s what I’d drunk for years before making the switch to raw milk from grass-fed cows.
“Yuck. This tastes burnt!” I said.
That’s when I saw it. The milk had been ultra-high temperature pasteurized. In fact, more than 80% of the organic milk sold in the U.S. is UHT pasteurized. It’s why I don’t drink organic milk.
What is UHT Milk?
The official U.S. government definition of an ultra-pasteurized dairy product stipulates “such product shall have been thermally processed at or above 280° F for at least 2 seconds, either before or after packaging, so as to produce a product which has an extended shelf life.”
Get this. According to Wikipedia, UHT milk has a shelf life of 6 to 9 months (until opened). When the world’s foremost UHT milk processor, Parmalat, first introduced UHT milk to the U.S. market back in 1993, they hit a snag. Americans distrust milk that hasn’t been refrigerated. We like our milk cold, and UHT milk doesn’t need to be refrigerated.
So, milk producers got creative. They could extend the shelf life of their product and not advertise that they were doing it. They’d sell the milk in normal packaging, in the refrigerator aisle, and none of us would be the wiser.
Now, almost all of the organic milk and the majority of conventional milk available in U.S. supermarkets is UHT processed.
What’s wrong with UHT processing?
The introduction to a 2005 study published in the Journal of Dairy Science highlighted the current problems with UHT processing from an industry point of view:
Often, heat treatment causes milkfat globule membrane proteins and whey proteins to unfold such that buried sulfhydryl (-SH-) groups, normally masked in the native protein, are exposed to the outer surfaces (Hoffmann and van Mill, 1997). In turn, these processes produce extreme cooked flavors, often attributed to changes in the sulfhydryl and disulfide content of the protein fraction (Swaisgood et al., 1987). Conventional pasteurization methods have long been in place and with the advent of UHT technology, the sterilization of fluid milk was achieved using higher temperature treatments for shorter periods. However, shelf-stable milk has met with limited acceptability by the consumer, especially in the United States, due in part to a high cooked flavor. Several attempts to improve the quality of UHT-treated milk products proved successful to varying degrees. Previously, Swaisgood and coworkers used immobilized sulfhydryl oxidase to reduce the thiol content of UHT-heated skim milk and described an improved flavor after enzymatic oxidation to form protein disulfide bonds (Swaisgood et al., 1987). Other studies have showed that altering UHT processing parameters, such as indirect vs. direct steam injection systems, cooling rates, and long-term storage conditions have a significant impact on sensory attributes (Browning et al., 2001). Most recently, epicatechin, a flavonoid compound, was added to UHT milk prior to heating, and the results revealed partial inhibition of thermally generated cooked aroma (Colahan-Sederstrom and Peterson, 2005).
So for decades, UHT processors have known that UHT processed milks results in a “high cooked flavor,” and they’ve done all kinds of experimenting to get rid of the nasty taste and smell (even resorting to adding flavonoid compounds to the milk to try to negate the off-flavor).
Okay, so it tastes funny compared to raw milk. And maybe it smells funny too. But what makes UHT processing any worse than regular old pasteurization?
According to Lee Dexter, microbiologist and owner of White Egret Farm goat dairy in Austin, Texas, ultra-pasteurization is an extremely harmful process to inflict on the fragile components of milk. Dexter explains that milk proteins are complex, three-dimensional molecules, like tinker toys. They are broken down and digested when special enzymes fit into the parts that stick out. Rapid heat treatments like pasteurization, and especially ultra-pasteurization, actually flatten the molecules so the enzymes cannot do their work. If such proteins pass into the bloodstream (a frequent occurrence in those suffering from “leaky gut,” a condition that can be brought on by drinking processed commercial milk), the body perceives them as foreign proteins and mounts an immune response. That means a chronically overstressed immune system and much less energy available for growth and repair. (source)
Now, that’s scary. No wonder more and more people are starting to think of themselves as intolerant to casein (the protein found in milk). Not only do pasteurization and UHT processing kill off the enzymes present in milk needed to digest the casein, the casein itself is altered to the point of being indigestible!
So now you know why I don’t buy organic milk at the store — even when I run out of raw milk. If you want more help deciding how to prioritize your milk purchases, check out this post on Healthy Milk: What To Buy.
Edited on 6/4/2013: Thanks to many reader comments, I’ve removed one erroneous paragraph in the original post! In it, I quoted a prominent leader in the real food movement about using UHT milk in ferments like yogurt or kefir. I no longer agree with the quotation, so I’ve simply deleted it. Thank you all for being such a thought-provoking and challenging community! All the best, ~Kristen