The investigation of the quality of milk pre-concentrated by an on-farm evaporation system : a thesis presented in partial fulfilment of the requirement for the degree of Master of Technology in Food Technology at Massey University

Pre-concentrating milk on-farm is likely to become an economical operation in the milk processing as the volume of milk processed in a dairy plant is steadily increasing, which means that the milk collection area is becoming larger and larger. A major concern of introducing the on-farm concentration system is the quality of pre-concentrated milk. The objectives of this study were to find out the most suitable evaporating temperature and the optimum concentration of milk to be done in an on-farm evaporator system. A Centritherm evaporator, which will be similar to the evaporator used in the on-farm evaporator system, was mainly employed to concentrate milk and a single tube falling film evaporator was also used for comparison in the experimental work. The effect of evaporation conditions on the changes in quality of pre-concentrated milk during the storage on farm, transportation from farm to processing factory, and the storage at factory were investigated. This consisted of two aspects: microbiological and