Characteristics of Organisms Contributing to Spoilage in Cottage Cheese

Effects of temperature, pH, sodium chloride, heat, and chemical germicides on the growth of 17 organisms isolated from spoiled cottage cheese were studied. None of the organisms grew at 3 C. for three days and 15 of 17 showed slight to profuse growth at 10 C. for seven days. All the organisms grew at pH 6.7 to 7.4. All except Torulopsis candida were retarded at pH 5.4 to 5.2 and lower. Fourteen of the 17 organisms grew in 5%, whereas only four grew in 7% sodium chloride. Pasteurizing at 61.7 C. for 30 rain. destroyed all organisms. Sorbic acid was not effective in concentrations up to 0.25% at pH 5.2 to 6.7, but was inhibitory at pH 4.8 and 5.0. Editor.