United States.
Rapid heating and cooling of milk significantly reduces the amount of harmful bacteria present, extending the milk's shelf life by several weeks, according to a Purdue University study.
Bruce Applegate, a Purdue associate professor in the Department of Food Science, and collaborators from Purdue and the University of Tennessee published their findings in the journal SpringerPlus, where they show that increasing milk temperature by 10°C for less than a second eliminates more than 99% of the bacteria left behind after pasteurization.
According to B. Applegate, it's an addition to pasteurization, but it can add shelf life of up to five, six, or seven weeks to cold milk.
The low-temperature, short-lived (LTST) method in the Purdue study sprayed tiny droplets of pasteurized milk, which was inoculated with Lactobacillus and Pseudomonas bacteria, through a heated, pressurized chamber, rapidly raising and lowering their temperatures by around 10 °C, but still below the 70 °C threshold required for pasteurization. The treatment reduced bacterial levels below detection limits, and extended the shelf life up to 63 days.
LTST camera technology was developed by Millisecond Technologies, a New York-based company.
Sensory tests compared pasteurized milk with milk that had been pasteurized and processed through the Millisecond process. The panelists detected no differences in color, aroma or taste between the products.
Phillip Myer, an assistant professor of animal sciences at the University of Tennessee and a co-author of the paper, said the process uses the heat already needed for pasteurization to quickly heat milk droplets. He added that the process significantly reduces the amount of bacteria present, and does not add any additional energy to the system.
Source: www.purdue.edu
