Defining Optimal Conditions for Making Cottage Cheese from Reconstituted Milk Powder

Cottage cheese was manufactured from milk powder reconstituted at solids levels ranging from 8.0 to 20%. The reconstituted cheese milk was held at 6°C for four time periods (0, 12, 24 and 36 h), followed by inoculation with 1 % bulk lactic starter. Values determined were yields expressed in three different ways and total solids. The study was first conducted in the laboratory using 3-L containers for each treatment effect. This was to be used as a screening technique with the optimal results then being tested under pilot plant conditions. The 0-hold resulted in a shorter setting time than any of the other hold periods. The four optimal solids levels obtained in the laboratory study were determined on the basis of moisture characteristics, yield, cost and setting time. Those solids levels evaluated in the pilot plant study were 10.5, 12, 13 and 15%. Two hold times were selected for the pilot plant study, with those being a 0-hold and a 12-h hold at 4.4°C. All results were compared to two controls, a non-fortified (9.0% total solids) and a fortified (10.5% total solids) skim milk. Cost comparisons at the various levels were made. Over all conditions of this study, cottage cheese made from 10.5% reconstituted non-fat-dry milk with a 0-hold appeared to be best as measured by moisture control, set time, cost, adjusted yield and appearance of curd at varying stages. In the pilot plant study, there was no significant (P<0.05) difference in any measurable parameter between the 0- and 12-h holding period. There was very little difference between the 10.5 and 12.0% cheese, except for price (12% cheese would cost 2 to 3% more per pound of dry curd than 10.5% cheese) and appearance of the curd (10.5% curd was slightly less matted with fewer "fines"). Work is presently underway to study creaming factors of this cheese. The two control cheeses were approximately the same as the 10.5% reconstituted skim milk cheese with regard to quality factors but were cheaper (about 10¢/.454 kg dry curd).