This Study was carried out to investigate yeast and mold contamination in fermented milk products produced by 10 different domestic manufacturers frond October 20 to December 5.1980. The results obtained in the study were as follows;
1. pH values of the products were ranged from pH 3.14 to pH 4.20 and average of sour milk drinks
was pH 3. 66=0. 19 and fermented milks pH 3.74_0. 09. Therefore the difference of pH avenges among
sour milk drinks and fermented milks was statistically significant. P<0.01)
2. In case of yeast contamination, yeast was found on all the four products produced at the same
date, From this result, it seemed that yeast contamination occurred during the manufacturing progress. 3. Degree of contamination by the indicator organisms was E. coli positive, 3.3,06; over 1, 000 yeasts/ml, 13.3 %; over 10 molds/ml, 1. 7 ´cc. 4. In the range of over 1.000 _yeasts/mi, degree of contamination by yeast was 5,6 % in fermented milk
and 16.7 in sour milk drink.
5. Yeasts in product D increased to the spoilage number within 5 days and in I increased within 10 days at VC. At 15´C, yeast increased to the spoilage number within 15 days in product B.E.
6. It seems that the yeast number of initial contamination should be important than the increase rate; as criteria on the fermented milk products.
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