As fresh milk cannot be kept for more than a couple of days, unopened, most is treated before sale. The vast majority will be homogenised, to stop the cream from separating from the rest of the ...
if you don't have a ready supply of buttermilk, you can make a quick substitution for buttermilk by souring some fresh milk. Add 1 tbsp of lemon juice to every 100ml of milk called for in the recipe.