Quality Characteristics of Mozzarella Cheese Manufactured with Recycled Stretchwater

Stretchwater from mozzarella manufacturing represents a waste that cannot be disposed into the public sewer due to high organic load. An experimentation was performed to evaluate the possibility of reusing it as a new stretching liquid for producing the cheese instead of pot water, after membrane nanofiltration treatment. One control and three experimental high moisture mozzarella samples were prepared at three different dairies by stretching the curd with water or stretchwater nanofiltration permeate recycled one, two or three times. The results demonstrated that the experimental cheeses were safe and had the same chemical and sensory characteristics as the control one. However, the long storage time of the curd waiting for the availability of the permeate proved to be a possible weak point. In fact, it was sometimes associated to worsening of the quality characteristics of the product obtained with stretchwater recycled three times. When the hygienic conditions of the dairy were optimal and pasteurized milk was used, no worsening was observed even after the third filtration treatment. The problem could be overcome by making the membrane treatment as a continuous process, in synchrony with the stretching phase.