Microfiltration of ceramic membrane forimproving UHT milk quality

In order to improve the quality of UHT milk, high somatic cell count (SCC) and low SCC raw milk were degermed by microfiltration (MF) with 1.4 μm ceramic membrane. Four groups of milk were obtained: low SCC milk, MF low SCC milk, high SCC milk and MF high SCC milk. Then the four groups of milk were sterilized with ultra high temperature (UHT) to prepare four groups of UHT milk, which were stored in 37℃ and the quality was evaluated between the microfiltration and non-microfiltration groups. The results showed that in the high SCC and low SCC raw milk, residual bovine plasmin activity was 4.1% and 3.28% left respectively after UHT, while it was almost eliminated during the procedure of "MF+UHT". Both the quality indexes of the "MF+UHT" milk, including non-casein protein (NCN), pH value, acidity and fat globule particle size, changed littler than UHT milk without MF and the quality kept better. Relative to the low SCC groups, the quality improved much more in the high SCC groups through microfiltration. The results can provide a reference for the use of high somatic cell milk to produce high quality UHT milk.