As a subscriber to Scientific American, I just read one of their regular columns “Ask The Expert” which asked “Why does organic milk last longer than regular milk?” That column is online here. Here’s the excerpt that caught my attention:
Organic milk lasts longer because producers use a different process to preserve it. According to the Northeast Organic Dairy Producers Alliance, the milk needs to stay fresh longer because organic products often have to travel farther to reach store shelves since it is not produced throughout the country. The process that gives the milk a longer shelf life is called ultrahigh temperature (UHT) processing or treatment, in which milk is heated to 280 degrees Fahrenheit (138 degrees Celsius) for two to four seconds, killing any bacteria in it. […]
Retailers typically give pasteurized milk an expiration date of four to six days. Ahead of that, however, was up to six days of processing and shipping, so total shelf life after pasteurization is probably up to two weeks. Milk that undergoes UHT doesn’t need to be refrigerated and can sit on the shelf for up to six months. Regular milk can undergo UHT, too. The process is used for the room-temperature Parmalat milk found outside the refrigerator case and for most milk sold in Europe.
So why isn’t all milk produced using UHT? One reason is that UHT-treated milk tastes different. UHT sweetens the flavor of milk by burning some of its sugars (caramelization). A lot of Americans find this offensive—just as they are leery of buying nonrefrigerated milk. Europeans, however, don’t seem to mind.
To summarize: UHT milk lasts longer and doesn’t need to be refrigerated, but Americans wouldn’t buy it because of taste or unfamiliarity. I’ve always wondered if this is why soy or rice milk is refrigerated when, with proper packaging, it doesn’t need to be kept cold until it’s opened.
However, it’s likely true that major costs of milk nowadays (in the era of >$4 gas) have to do with shipping and refrigeration from minute it leaves the cow to the minute it’s poured on your cereal. Besides what’s done on an industrial scale, how could one begin to calculate the amount of energy used to chill the milk sitting in millions of home refrigerators, or how much milk is poured down the sink because it’s past due? Imagine how much smaller the carbon footprint of un-refrigerated boxed UHT milk (organic or not) would be compared to traditional milk. I don’t know for a fact that UHT milk is a net win environment-wise, but I have a strong hunch that it can’t be worse than what we do now.
Is it time us to try UHT milk again? If people have no problem spending more for UHT organic milk and don’t mind the taste (I buy UHT organic and didn’t even realize until looking in to all this), would the rest of the country try UHT nonorganic milk if it meant saving a dollar and/or helping the environment to boot?
Some additional links I found on the subject:
- Wikipedia: Ultra-high temperature processing
- Interesting Thing of the Day: Milk in a Box
- Times Online: The UHT Route to Long-Life Planet