A total of one hundred random samples of heat treated milk (pasteurized and UHT, 50 of each) were collected randomly from Groceries and super markets at local markets in Alexandria Governorates for chemical, sanitary and microbiological evaluation. Mean values of fat, protein, lactose, SNF and minerals of examined pasteurized and sterilized (UHT) milk were (2.5±0.16, 3.3±0.6), (3.3±0.07, 3.4±0.07), (5.4±0.25, 5.7±0.27), (8.7±0.16, 9.07±0.25) and (0.51±0, 02, 0.54±0.02), respectively. Sanitary evaluation of examined pasteurized and UHT milk samples was revealed that, the mean values of titratable acidity and pH values were (0.15±0.0025, 0.14±0.002) and (6.66±0.06, 6.65±0.03) respectively. Microbiological evaluation revealed that the mean values of total bacterial count in examined pasteurized and sterilized (UHT) milk samples were (6.9 x102±0.74 x102 and 4.7 x102±0.73 x102), respectively. On the other hand, total Coliform and faecal Coliforms count were found with mean values of (5.7 x102±0.6 x102 and 1.5 x102±0.45 x102) for Coliform organisms while, (8.0 x10±0.45 x10 and 4.5 x10±1.5 x10) for faecal Coliforms, respectively. Entero Pathogenic E.coli organisms were failed to be detected in all examined pasteurized and sterilized milk samples. Clostridia organisms were detected in a percent of 14 and 12% in examined pasteurized and UHT milk samples with a mean values of (2.4 x10±0.57x10 and 3.8 x10±0.83 x10) respectively. The most prevalent isolated clostridia species were Clostridium Chauvoei, Clostridium septicum, Clostridium novyi, Clostridium perfringens with variable percent of (2, 3, 3, 0 and 4, 3, 3, 1) in both examined pasteurized and UHT milk samples, respectively. Mean values of isolated yeast count from pasteurized and UHT milk samples were (1.7x10±0.3 x10 and 1.3x10±0.2x10) with incidence percent of 12% in both samples, respectively. On the other hand, the mean values of mould count were (2.8x10±0.24x10 and 7.5x10±0.97x10), respectively. Incidence percent of mould contamination was 84 and 88% in both examined pasteurized and UHT milk samples. On the other all the prophylactic hygienic measures should be undertaken to safe guard the consumer health and prevent contamination of heat treated milk
Key words: Pasteurized milk, UHT milk, Coliforms. E.coli, Clostridia, Yeast, and mould
|
