Why does carton milk taste different from plastic bottle milk when both are pasteurised?

Question

Same brand too:

[https://groceries.asda.com/product/long-life-milk/asda-long-life-semi-skimmed-milk/20525](https://groceries.asda.com/product/long-life-milk/asda-long-life-semi-skimmed-milk/20525) (carton)

[https://groceries.asda.com/product/semi-skimmed-milk/asda-semi-skimmed-milk/20504](https://groceries.asda.com/product/semi-skimmed-milk/asda-semi-skimmed-milk/20504) (plastic)

In: 1

Answer 1

Milk is almost always pasteurized (heated to a high temperature briefly to kill bacteria), but shelf-stable milk is pasteurized at a higher temperature. That higher temperature results in chemical changes in the milk, which makes it have a slightly different taste.

As for why: refrigerated milk only has to kill *most* of the bacteria living in it, because the cold temperature slows their growth enough to keep the milk good for a while. But to sit at room temperature, the milk has to be sterilized, which requires higher heat.