The goal of pasteurization is to kill of harmful pathogens. If you do this early and package and store the milk in the right conditions it can be stable and safe for a long time.

If you don’t pasteurize the milk and leave it for a long time, pathogens in the milk, such as bacteria, can potentially produce toxins. Boiling it at that point might not help, no, as it kills the bacteria, but can leave behind the toxins.

So pasteurization is very effective if done early, but you can’t do whatever you want to the milk and then pasteurize it right before using it and everything is good.

If all things are equal except for mass. Then the object of higher mass will fall faster.

Hi. Physicist here. You are absolutely wrong. The mass of an object does not affect the magnitude of force of air resistance which acts upon a falling object. But the acceleration that object will have is given by Newton’s second law as Force divided by mass. So a heavy and a light ball with the same shape will experience the same air resistance, but the heavy ball will “care less” and thus fall faster.