University of Khartoum

Chemical and Microbial Properties of Commercial Mish during Storage Period at Retailers Market

Chemical and Microbial Properties of Commercial Mish during Storage Period at Retailers Market

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Title: Chemical and Microbial Properties of Commercial Mish during Storage Period at Retailers Market
Author: Barakat, Mazza Abdelmonem Elfaki
Abstract: Mish is traditional fermented milks that contain high total solids, protein, fat in addition to the spices; it might be consumed alone or with the meal; Mish is produced by different dairy companies. The percentage of components of mish differ from producers to another; the mish store in the groceries for a period of 21 days (shelf life) in poor conditions, which might affect its chemical and microbiological properties. This study aimed to evaluate and compare the effect of storage period on the chemical and microbiological properties of mish collected from three companies of dairy products; C1, C2 and C3. Thirty samples of mish (ten per company and five per period and batches (day 2 and day 20) were randomly collected from groceries and transported to the laboratory of the Department of Dairy Production, Faculty of Animal Production, University of Khartoum. The samples were subjected to chemical (fat, protein, total solids, ash, acidity, and pH) and microbiological analysis (total viable bacteria, coliform and yeast and mold counts). The data were statistically analyzed using Statistical Analysis System (SAS ver, 9.1.3). General liner model was used for statistical analysis and means were separated by Duncan Multiple Range Test at P˂0.05. The result revealed highly significant (P˂0.001) variations of mish samples on chemical content between companies. Results obtained for the overall means of protein, fat, total solids, ash, acidity and pH were, 8.08%, 5.05%, 20.91%, 1.917%, 2.015%, and 4.4, respectively. The protein and fat content revealed highly significant (P˂0.001) differences for mish samples tested at day 2 (8.55%, 5.53%) decreasing to day 20 (7.61% and 4.57%) respectively, of storage period. The total solids value increased significantly (P˂0.01) from day 2, which revealed (21.43%) to day 20 (20.39%) of storage period; However the ash content showed non-significant (P>0.05) differences between the periods of storage (2.024% at day 2; 1.810% at day 20). The acidity content showed highly significant (P˂0.001) increase from day 2 for mish samples (1.794%) to day 20 (2.237%) of storage period, while the pH content showed highly significant (P˂0.001) differences decreasing (4.08 to 3.57, respectively from day 2 to day 20). The microbiological analysis results showed that log total viable bacterial count (6.120) and coliform count (5.872) revealed non-significant (P>0.05) differences between those companies. The effect of periods of storage showed that the total viable bacteria and coliform showed log 6.090 and log 5.858 for day 2 respectively, while the respective values were log 6.149 and 5.886 for day 20 of the storage period. Yeast and mold showed highly significant differences (P<0.001) between mish produced companies, which recorded a mean of log 5.326; Also it increased from day 2 (log 5.034) to day 20 (log 5.619) during the storage periods. This study remarked that there were variations between and within mish producing companies in their chemical and microbial properties. This might be related to the raw material that was used for processing of mish, in addition to the variation of production and processing methods and the storage conditions. Hence this study recommended consumption of mish during the beginning of its shelf life with consideration of its storage.
Description: 103 Pages
URI: http://khartoumspace.uofk.edu/123456789/26697


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