Application of Helical Viscometry to Study Commercial Mozzarella Cheese Melting Properties

Mozzarella cheese from two cheese plants (A and B) was collected biweekly for 10 wk.Five vats of cheese were sampied from a day's production.Cheeses were vacuum packaged and held at 4"C for 12 d.On d 12, cheeses were analyzed for composition (fat, total solids, calcium, salt) and apparent viscosity (a measure of cheese melting properties) by helical viscometry.Two cheeses from each plant also were held vacuum packaged at 4"C for 1 mo and analyzed weekly for apparent viscosity.During the survey period, plant A reported severe starter problems attributed to bacteriophage; plant B reported no problems in manufacture.Plant A experienced greater vat-to-vat and week-to-week variation in cheese composition and apparent viscosity than plant B. Cheese composition had a profound impact on Mozzarella melting properties.Cheeses stored at 4"C for 1 mo showed large initial differences in apparent viscosity but a common pattern of progressive decrease in apparent viscosity over time.Mozzarella functionality developed in two distinct but interrelated phases.The first phase occurred during manufacture when basic curd structure was established.A second phase occurred during storage when functionality and curd structure were altered.Helical viscometry offers new oppommities for the study of Mozzarella melting properties.