Squeezing More Shelf Life Out Of Milk

[rgiridhar]

Squeezing More Shelf Life Out Of Milk

Putting the squeeze on milk may be a long-sought solution to the search for improved ways of killing harmful bacteria in milk and increasing its shelf life without introducing off-flavors into the beverage, researchers report.

Michael C. Qian and colleagues at Oregon State University point out that ultrahigh-temperature pasteurization (UHT) does produce milk that stays fresh at room temperature for six months. They add, however, that UHT leaves a "cooked" flavor in milk that has limited the popularity of UHT milk.

In experiments published in the Nov. 29 issue of the ACS biweekly Journal of Agricultural and Food Chemistry, they describe how a new food processing technology affects the taste of milk. Called high hydrostatic pressure processing (HPP), it involves putting foods under pressures that crush and kill bacteria while leaving food with a fresh, uncooked taste.

"Milk processed at a pressure of about 85,000 pounds per square inch for five minutes, and lower temperatures than used in commercial pasteurization, causes minimal production of chemical compounds responsible for the cooked flavor. HPP gives milk a shelf life at refrigerated temperature of at least 45 days," they note.