The new method is able to significantly increase the storage time of milk before it sours. Until now, the shelf life of milk has been extended by pasteurization. The method was developed back in the 19th century by the French microbiologist Louis Pasteur and is available to almost any housewife.
Following traditional pasteurization, so that fresh milk just bought on the market "lasts" for 2-3 weeks, it needs to be heated to a temperature close to boiling for a short time. The best option is up to 75 ° C for 20 seconds.
Researchers at Purdue University, led by Bruce Applegate, have developed a simple addition to Pasteur's technology to bring milk to seven weeks.
The essence of this technology is that milk is heated over low heat simultaneously with a short-term change in pressure, after which it is cooled to 4 ° C. Experiments have shown that in just a second of such drops, up to 99% of the bacteria remaining after pasteurization die. It is equally important that the quality of milk does not change for the worse.
Scientists hope that their technology will reduce milk losses during long-distance transport and subsequent storage.