Design, Development of a Milk Pasteurization System

Existing pasteurizers have problems like holding coil contamination during diversion, reinfection through back growth of microorganisms from return lines and syphonage of raw milk into pasteurized line due to vacuum creation during diversion. To overcome these problems, a new pasteurizer was designed as per the quality guidelines for effective and hygienic pasteurization of milk. The developed pasteurizer was tested at raw milk inlet temperature of 2, 4, 6 and 8°C and total milk solids of 15 and 18 per cent. The pasteurization temperature of 78 to 80°C was used for 20 s. The pasteurizer was tested for overall heat transfer coefficient, regeneration efficiency, total heat load and pressure drop. The logarithmic mean temperature difference was used to find the running time of the newly developed system. The pasteurized milk side was always at higher pressure than raw milk side. The product side was also at higher pressure than hot and chilled water side. The measures were found to be effective to avoid the cross contamination.