ABSTRACT
In 1899, Hite (1899) subjected milk to high hydrostatic pressure instead of high temperature to keep it from turning sour. His attempt was inspired by the sensory shortcomings of heatsterilizedmilk, which had a ‘‘cooked’’ taste, and by his knowledge of recent discoveries in the field of marine ecology, in which researchers had demonstrated that microorganisms are affected by pressure. Hite achieved a 4-log reduction in microbial count in milk with a 10min treatment at approximately 700 MPa at room temperature. A 30-min treatment at 400 MPa successfully preserved grape juice, cider, peaches, and pears without destroying the fresh flavor. Below 200 MPa, the lethal effect of pressure was found to be significantly reduced, which was in agreement with earlier findings of Chlopin and Tammann (1903). These authors already reported the resistance of bacterial spores to hydrostatic pressure, which was later proven by Larson et al. (1918). These authors found that a pressure of even 1200 MPa was not sufficient to kill Bacillus subtilis spores.
