Microbiological quality determination of pasteurized, UHT and flavoured milk sold in Dhaka, Bangladesh

Abstract

The present study was undertaken to determine the microbiological quality of pasteurized milk, UHT milk and flavoured milk samples collected from different locations in Dhaka, Bangladesh. Twenty pasteurized milk samples, fifteen UHT milk samples and fifteen flavoured milk samples of different brand were collected and different batch were analyzed for enumerating the total viable bacterial count (TVBC), total coliform count (TCC) and physiochemical tests (sensory test, alcohol test, acidity test, fat test, CLR test, SNF). The range of TVBC and pasteurized milk samples was between 2.3×10² cfu/ml to 4.69×10³ cfu/ml. TVBC range of flavoured milk samples was between 5.0×10¹ cfu/ml to 1.8×10² and no TVBC was detected for any of the UHT milk samples. No TVBC was found for flavoured milk samples of company-8 (UHT). Because it was processed with ultra high temperature, slightly lower than that recommended by BSTI (not exceeding 20,000 cfu/ml). Coliform bacteria were present only for pasteurized milk samples in one brand, though the count was under acceptable range according to BSTI recommendation (<10/ml coliform in pasteurized milk). Physiochemical tests are also very important to detect the quality of milk samples. Acidity range should not exceed 0.14, for this study fat range should be minimum 3.5% and SNF should be minimum 8%. In this study, for pasteurized milk samples acidity range was between 0.14-0.16, fat range was between 3.5-3.9% and SNF was between the ranges of 8-9.784%. For UHT milk samples acidity range was between 0.13-0.16, fat range was between 3.5-3.8% and SNF was between 8.034-9.012. All the results of sensory and physiochemical tests for pasteurized and UHT milk samples were satisfactory. So, UHT processed milk and flavoured milk can be considered as safe for consumption within the mentioned expiry date without heat treatment.

Stamford Journal of Microbiology, Vol.8(1) 2018: 1-6