How to guarantee the biological stability of beer?

Generally the consumers judge the beer with the standard of freshness, clarity, foam and colors. For this to happen, the first step is to ensure the biological stability of beer.
During the whole process of beer brewing, the beer equipment should be totally washed and sterilized, it is very important to the biological stability of beer. Besides, there are two main methods to keep the beer stability -- Pasteurization & Cryogenic membrane filtration.
1.Pasteurization
The pasteurization temperature should be controlled strictly to avoid damaging the beer flavour. The higher temperature would damage the beer body/mouthfeel. Compared with tunnel pasteurization, now the instantaneous sterilization with significant advantage and being more and more popular, but it with much higher requirements for the beer bottles and the bottling skills.
2.Cryogenic membrane filtration
The tunnel pasteurization and instantaneous sterilization are more well-developed methods to keep the beer stability. But the thermal treatment will cause some changes on the embedded substances in the beer. Under a lower temperature, this could be better avoided with membrane filtration which could help to remove the microorganism in the beer.
3. And some notes during the membrane filtering
(1). The beer with good filterability
(2). Strictly inspection is must needed to avoid any pollution, especially the water, CO2 and the parts they may touch with air.
(3). Both of the beer bottler and capper should reach Sterile Assurance Level