Effects of Reducing Rennet and Adding Calcium Chloride on the Manufacture and Curing of Cheddar Cheese

This study showed the lack of-rea~ benefits derived from using low levels of rennet with added calcium chloride in the manufacture of Cheddar cheese.Cheese was made from raw and pasteurized milk during four seasons.Each lot of cheese consisted of three vats to which 90, 45, and 45 ml.rennet per 1,000 lb. of milk was added, respectively.The third vat of milk was further treated with 0.02% calcium chloride.The cheese was cured at 50 ° F. for 36 wk.Using subnormal amounts of rennet delayed curd formation in both raw and pasteurized milk.Adding 0.02% calcium chloride with one-half normal amounts of rennet gave normal curd formation and yield, but protein breakdown was slow, and curdiness persisted longer in the finished cheese.The quality of the cured cheese was not influenced by variations in the rennet and calcium chloride used, but persistence of curdiness was undesirable in young cheese made with reduced levels of rennet, especially when supplemented with calcium chloride.Adding calcium chloride to milk for cheese-making reduces the amount of rennet needed for optimum curd formation (12,17), improves curd-making properties under certain conditions (29), and may increase the yield of cheese (14,17,21).The use of calcium chloride with less rennet has been advocated by some practical operators for reducing costs.The Federal Definitions and Standards of Identity (8) permit the addition of the equivalent of 0.02% anhydrous purified calcium chloride to milk for cheese-making.It is the purpose of this paper to report the results of using reduced amounts of rennet, with and without calcium chloride, on the manufacture and ripening of Cheddar cheese made from raw and pasteurized milk.The factors observed were: curd firmness at cutting time; recovery of milk solids in the cheese; extent of ripening in terms of proteolysis and fat hydrolysis at 8 and 36 wk. of age, and cheese quality at 2, 8, and 36 wk. after making. EXPERIMENTAL METHODSCheese-making.The milk came from the mixed milk supply of the University of Wisconsin dairy manufacturing laboratory.Cheese was made in September, December, March, and July, to represent milk from four seasons.Four lots of cheese were made in each of these months: