Nutritional and Microbiological Quality Assessment of Pasteurized Milk in Azh Agro Industries Pvt. Ltd., Gazipur, Bangladesh

Abstract

Milk is one of the most valuable and regularly consumed natural food which is rich in nutritional value. A study was carried out with raw liquid milk collected from Shahzadpur and pasteurized, packed in AHZ Agro Industries Pvt. Ltd, Gazipur, Bangladesh. One hundred and forty five pasteurized milk samples collected from August, 2011 to February 2012 were analyzed for the nutritional and chemical composition such as acidity, fat, solid non fat, protein, lactose, specific gravity; and microbiological characteristics. Platform tests (alcohol and clot-on-boiling) were found negative. From the study it was found that the nutrient composition of the pasteurized milk samples were within the standard limits with average specific gravity of milk was 1.029, fat 3.575%, protein 3.43% and lactose 5.02 %. Acidity% refers the quality of milk. The 7 months average highest acidity was 0.15% and the lowest acidity was 0.146%. Protein percentage was found to be 3.36% in August (Rainy season), 3.45% in winter and 3.42% in spring. All the samples had solid non fat (SNF) with standard limits of 8.17 to 8.38 percent. It was found that total bacterial count in milk varies with seasons. In rainy season, autumn season and winter the average total viable count was 1715, 1744.3 and 1481.6 cfu/ml respectively. From 145 pasteurized milk samples, 121 samples showed excellent quality and 24 samples showed good quality in methylene blue reductase test (MBRT). No coliform and Salmonella/Shigella were observed. SNF and protein percentage varied with season, been highest in winter while less in spring. The overall result found was ensuring good quality of pasteurized milk. All the nutritional composition and microbiological count complies with the BSTI standard.