There are millions of bugs in milk, they are so tiny that we need microscope to see them. Because of their micro size, they are called Microbes or Micro organisms (i.e., bacteria, yeasts and mold).
These microbes are diverse in everything, from their size, shape and their motility to their nutrient requirement. As milk is composed of many types of nutrients, you will find microbes eating any one of those nutrients.
Surprisingly, milk is free from bugs when it is inside Cow’s udder, provided animal is healthy. As soon as milk is out, bugs find their way to enter in it. It is very easy for them and their entry is unavoidable because our environment is full of them. When milking is done, Milk gets contaminated with these bugs from animal outer skin, from utensils, from the milker’s hand, his cloths and the surrounding of animal. This does not stop, milk travels further from milking vessel to other cans, from their to tankers, chillers, dump tanks etc. and each step adds up to the number and variety of bugs in it.
But, we need not to get scared of them until and unless, they are very high in number or some extremely bad bug has found its way to take a feast in milk.
If, somehow, BAD BUGS enter milk, you can get really sick…. you may get infections and some microbes cause really bad infection. But this will happen only if milk is being handled very poorly or it is milked from a not-so-healthy cow by sick persons. That is why, milk is heated before consumption, because heating will kill all bad bugs and also other bugs come down to safer number. But… if heating process is rigorous, precious nutrients are lost from milk.
So, if you consume milk just after milking, right at the farm, you will probably get best of it, without any loss of nutrients and least possible number of microbes.
Well, there are good bugs as well, they help us to become so strong that our body will fight any bad bug trying to make their colony in our body. These good bugs are found in Curd, Dahi etc.
Milk, that you are getting from shopapni, http://www.shopapni.in/category_listing.php/dairy has least number of bugs and there are no bad bugs, as milk is drawn from healthy animals by healthy people, with utmost sanitation and hygiene. Still, keep carrying out Indian practice of boiling milk before consumption (even if it is processed milk).