Dear grzbear, thank you a lot for your reply.
The thing is I use to buy also raw cow´s milk from the same shop /same dairy but then I switched mainly to goat´s milk which is REALLY expensive over here because I learnt about its health benefits/I love everything-goat-in-it (cheese, youghurt, milk, bath soaps etc), BUT mainly because goat´s milk seems to be much more resiliant to that "funky puky smell" phenomenom I have been experiencing (or maybe the goatines masks it better). Cow´s milk picks up the smell and taste much quicker and stronger than goat´s milk. It is not the smell of goat itself that bothers me (I love really strong tastes in food) it is rather "the pukes" bit that really makes me sick to my stomach. I buy 5 liters of the milk at the same time because the shop gets it only once a week. I store it in the fridge and first couple of days everything seems to be fine but already third day (eg fourth day after packinging) milk starts to have THAT weird smell and taste. I would love to buy fresh milk every time to make my kefir from but it is not simply possible. My last batches of kefir get already "the smelly" stuff but goat´s version is still bearable to me. Still, I have to switch to regular shop´s milk for three last days of the week or put my grains to hibernation because by that point old raw milk would be off and new fresh one wouldn´t have arrived to the shop yet.
Sorry for such a lenghty elaborate and thanks once more for your help.