Spoilage in milk, and risk of food poisoning, happens because of the presence of harmful bacteria. That is why pasteurization saves so many lives and the raw milk food fad has orders of magnitude greater risk of causing illness.
It's also why an "add-on" to pasteurization can extend the shelf life of milk by several weeks, which reduces food waste and therefore is less strain on the environment. Where pasteurization is a high-temperature, short-time method that gives milk a shelf life of about two to three weeks, the new technique,which involves increasing the temperature of milk by 10 degrees Celsius for less than a second, eliminates more than 99 percent of the bacteria left behind even after pasteurization.
The low-temperature, short-time (LTST) method developed by Millisecond Technologies of New York was validated in a recent study by spraying tiny droplets of pasteurized milk, which was inoculated with Lactobacillus and Pseudomonas bacteria, through a heated, pressurized chamber, rapidly raising and lowering their temperatures about 10 degrees Celsius but still below the 70-degree Celsius threshold needed for pasteurization. The treatment lowered bacterial levels below detection limits, and extended shelf life to up to 63 days.
"With the treatment, you're taking out almost everything, Whatever does survive is at such a low level that it takes much longer for it to multiply to a point at which it damages the quality of the milk," Bruce Applegate, Purdue associate professor in the Department of Food Science, said in their statement.
It requires no extra energy, since the heat for pasteurization is already used, and after reducing the bacteria panelists could not detect differences in color, aroma, taste or aftertaste between pasteurized and LTST milk. They intend to see if it can simply replace pasteurization in the next study.