Purdue researchers develop new method that could keep milk fresh for two months
WEST LAFAYETTE, Ind. – It’s a terrible feeling—you take the milk out of the refrigerator, take a sniff and realize it’s already gone bad.
But your gallon of milk may not have such a short shelf life soon, thanks to researchers at Purdue University who have developed a method that will make milk last for two months.
Typically, pasteurization is done one of two ways: by using a “high-temperature, short-time treatment” of 161 degrees Fahrenheit or a “low-temperature, long-time treatment” of 145 degrees for 30 seconds. Those methods mean milk lasts two or three weeks before bacteria take over and the milk goes bad.
But Bruce Applegate, an associate professor in Purdue’s Department of Food Science, in collaboration with other researchers at Purdue and the University of Tennessee, found that increasing the temperature of milk by 10 degrees for less than a second eliminates more than 99 percent of bacteria left behind after pasteurization.
Applegate said the method can add “up to five, six or seven weeks” to cold milk. The low-temperature, short-time method used by Applegate sprays tiny droplets of pasteurized milk through a heated, pressurized chamber developed by a New York-based company called “Millisecond Technologies.”
“With the treatment, you’re taking out almost everything,” Applegate said. “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.”
Panelists couldn’t detect any differences in color, aroma, taste or aftertaste while comparing milk run through the new process with milk that had been pasteurized in the usual way.
Applegate and his fellow researchers said the method will enable milk to last longer and allow distributors to send it to distant locations where it would otherwise have a short shelf life.
The results of their tests were published in the journal SpringerPlus.