الفهرس 
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Abstract
The main experiments were carried out during the period from April to June 2018 in Zahar dairy factory at the new town of Salhiya, Sharkia Governorate, Egypt to develop and evaluate the performance of milk pasteurization unit.
The main objective of the present investigation was to use the modern technological modifications for the pasteurization process. To achieve the ultimate goal, the following criteria were taken into consideration.
- Develop the original milk pasteurization unit by adding a pneumatic regulating valve to improve its performance.
- Select the optimum operating parameters (heating temperature, vapor pressure and cooling temperature) affecting the performance of the pasteurization unit.
- Compare the final pasteurized milk quality produced from the pasteurization units before and after development. The performance of the milk pasteurization unit was experimentally measured under the following parameters:
- Four different heating temperatures (70.0, 74.0, 77.0 and 80.0 oC).
- Four different vapor pressures (200, 400, 600 and 800 kPa).
- Four different cooling temperatures (3 , 4 , 5 and 6 oC)
Evaluation of the milk pasteurization unit was carried out taking into consideration productivity, specific energy, operational cost and quality from standard quality view.
The experimental results revealed that pasteurization unit productivity (258 kg/h), heating rate (4.9oC/s), fuel consumption (144 l/h), energy requirements (1.74 kW.h/kg) and bacteria count (25/ml), were in the optimum region under the following conditions:
- Using the developed unit for the milk pasteurization process.
- Adjusting the milk pasteurization unit at 74oC heating temperature and 400 kPa vapor pressure.
- Adjusting the pasteurizer cooling system at 4oC cooling temperature.