Chemical and Microbiological Qualities of Certain Local Dairy Products in Assiut City تقییم الجودة الکیمیائیة والمیکروبیولوجیة لبعض منتجات الألبان بمدینة أسیوط.

Abstract

Thirty samples (10 raw milk, 10 yoghurt and 10 cheeses) were randomly collected from local markets in Assiut city. All samples were chemically analyzed for acidity, fat, total nitrogen, soluble nitrogen, salt and ash contents, microbiologically for total counts of bacteria, molds & yeasts and for the incidence of coliform bacteria. The obtained results were (0.13-0.20), (0.63 – 0.81) and (0.27-0.97) for  titratable acidity, (3- 7.3), (3.0-4.7) and (1.00- 35.00) for fat contents, (0.47-0.60–), (0.70-0.83)  and (2.05-3.7)  for total nitrogen (TN%), (0.28-0.45), (0.011-0.029  ) and(  0.014-1.33   ) for soluble nitrogen ( SN%) , ( 0.17-0.29), ( 0.16- 0.31) and (2.34 – 9.56) for salt contents and  ( 0.40 -1.05) , ( 0.70 – 0.89) and ( 2.5 – 7.52)  for ash contents  of liquid raw milk, yoghurt and cheese samples respectively. microbiological analysis the total bacterial counts (TBC) were  (2.25×105 -  5.25× 107), (4.9 ×105 -  7.25× 107) and ( 4.1 ×105 -  18.75× 107),  molds & yeasts ( 1×102 - 45×102 ),( 1×102 - 40×102 )and  ( 1×102- 17×102 )   for liquid raw milk, yoghurt and cheese samples respectively. The results also showed that,  most of the investigated samples were free from coliform bacteria except for raw milk.