Effect of Different UHT Processing Temperatures on Ash and Lactose Content of Milk during Storage at Different Temperatures

Commercial milk and improve quality milk containing total plate count 2.2 x 106 and 3.5 x 105 cfu/mL and somatic cell count 621,000 and 249,000 per mL, respectively were subjected to different ultra-high temperature (UHT) processing temperatures (135, 138, 141 & 144oC) and stored at 25oC and 40oC temperatures for 90 days. Commercial milk contained significantly lower content of lactose as compared to improved quality milk. More degradation of lactose content was observed in milk stored at 40oC than at 25oC temperature. The lactose content decline in UHT milk processed at a temperature 135oC was lower than at 144oC temperature. Commercial milk possessed higher ash content than improved quality milk. UHT processing and storage temperatures had no influence on ash content of both milk sources. © 2010 Friends Science Publishers