The myth of organic shelf life
“There’s nothing inherent about organic milk that makes it last longer [than conventional milk] at all,” explains Lori Hoolihan, Ph.D., R.D.N., manager of nutrition research at the Dairy Council of California. “The term ‘organic’ is really just about the way the cows were treated, and the way the milk was produced.”
OK. Debunked. That was easy. But those differences in expiration dates must come from somewhere. And that “somewhere” is in the pasteurization process.
Pasteurization: hot vs. really, really hot
The pasteurization process is a heat treatment for milk that ensures you aren’t swallowing any diseases along with your cookies. It destroys disease-causing microorganisms, spoilage microorganisms, and enzymes that can damage you or the final product.
If organic milk is processed using ultra-high temperature (UHT) pasteurization methods -- which involves heating milk to 290 to 302 degrees fahrenheit for up to two seconds -- then it will be shelf-stable for much longer than it would via lower-temperature methods, like vat or high-temperature pasteurization, Hoolihan says.
Regular milk can be ultra pasteurized, too. In fact, if both organic and regular milk are pasteurized in the same manner and held at the same temperature and time prior to purchase, they would last the same amount of time, according to Craig Baumrucker, Professor Emeritus of Animal Nutrition and Physiology at Penn State.
Yet, commercially, organic milk is more commonly given the UHT treatment. That’s because there’s a greater need to warehouse organic milk and truck it longer distances, Maltby says.