Evaluation of Physicochemical and Microbial Properties of Mish during the Shelf Life after Hazard Analysis and Critical Control Points Implementation

Abstract

This study was conducted to analyze hazards, determine the critical control points (CCPs) and ensure the safety of fermented dairy product (Mish) during manufacturing process and during the shelf life by using Hazard Analysis and Critical Control Points (HACCP) system to verify the quality and good manufacturing practices (GMP) in Dal Dairy Factory (CAPO) and observe the changes happening to the product during the shelf life. HACCP plan was set, the critical control point (CCPs) were identified based on the flow diagram of Mish production line. Control measures including, physicochemical and microbial analysis were determined to raw milk samples, during mixing, after pasteurization, fermentation process, after packaging of the product and during the shelf life. Critical limits, monitoring procedures were set and the results obtained were statistically analyzed. The physicochemical results of raw cow milk were (pH 6.70, specific gravity (SG) 1.03, titratable acidity (T.A) 0.16, fat 3.71%, solid nonfat (SNF) 8.90, total solids (TS) 12.61%, protein 3.28% and moisture 87.39%). Milk samples were nil of antibiotics during the study period. In raw milk The microbiological results indicated that Coliform bacterial count were 3.8*104 cfu/ml and total bacterial count (TVBC) were 4.8*105 cfu/ml. milk was prepasteurized at 75 C for 15 sec and standardized by adding whole milk powder and skim milk powder, The mixture pasteurized at 95C/5minutes and cooled to 44C (optimum temperature for adding culture and fermentation) this process were done in three batches. The physicochemical results of mixture before pasteurization were (fat 7.068%, SNF 20.000%, TS 27.067%, SG 1.070, protein 6.533% and moisture 72.93%); while after pasteurization were (fat 6.967%, SNF 20.000%, TS 26.800%, SG 1.068, protein 6.367% and moisture 73.200%). There were significant differences (p0.05) in TS, SG and moisture but there were no significant (p>0.05) differences XIII in fat content, solid nonfat and protein before and after pasteurization. The fermentation process accomplished in 4-6 hours until pH reached 4.5, and the curd was cooled to 20C. After cooling the spices (salt, garlic and roasted fenugreek and black cumin) were added and mixed with the curd until homogenized and mish was ready for pumping into the packaging machine. The samples were taken after packaging from the three batches and stored in refrigerator at 4-10 C to detect the microbial and physicochemical changes during the shelf life. During the shelf life there were significant differences (p0.05) in physicochemical properties such as pH, viscosity, SNF, T.S, density, acidity and lactose; but there were no significant differences (P>0.05) in the fat and ash content, and minute different in protein and moisture. The results for microbial growth showed that there were no growth of yeasts and moulds and coliform was nil. The study indicated that the microbial and physicochemical properties of CAPO Mish are within the Sudanese standards limits and standard range of Mish in the plant. Therefore, application of the HACCP could contribute to safe and high quality Mish.