Spoilt milk-silly question

Ok, just had a morning workout, been using supplements sa whey protein with water for the past few weeks, this morning decided to have it with milk, so put in 200ml of milk in shaker, scoop of whey(very sweet if anyone tried supplements sa) was tired and thirsty so downed it in one gulp, got a slight cold so didnt get any smell, but realised towards the end the taste was not right, checked the milk bottle, expired. Sooo do i have to worry about food poisening or anythin after consuming spoilt milk? Anyone?

No you don't. I was fine

Nope, I will reply later why milk turn sour in the first place. You have nothing to worry about, because drinking sour milk is very common and before pasteurization many people deliberately made their milk sour.

Thanks for the feedback. Look forward to your later reply/explanation admin...

There are many bacteria living in raw (unpasteurized) milk and these will metabolize (also called fermentation) the sugars (lactose in this case) in the milk and produce lactic acid. It's the lactic acid that gives milk its sour taste because it will lower the pH. This is very similar to the way alcohol is produced in wine ect.

Under normal conditions this is not harmful to us at all, however there is always the possibility of bad bacteria entering milk through unhygienic milking practices and for this reason milk is pasteurized to kill or lower most of the bacteria in milk. The disadvantage of this is that milk will not easily turn sour but will decompose instead.

So if you drank sour milk you will be fine, but if you drank rotten milk you might become ill.