I use Pasteurized Amul milk (see here). Last time, I purchased it on May 3rd and has expiry as today, 05-05-19.
(Outside temperate in our area is around 35-40 degrees)
I keep it (packaged when not boiled, in pan once opened and boiled) in the fridge all the time except when it is used. I first brought it out on May 4th morning, boiled it and used half of it (total 500 ml). Stored the remaining again in fridge in pan.
I boiled the remaining milk just a few minutes ago (tonight will be expiry).
Here's what I observe:
- Mostly, I see no layer or negligible layer when I first boil the milk on 4th
- When I boil it again next day in same pan (I don't change the pan during whole process), there's still fat in it, a creamy yellow layer on top but the bottom layer (highlighted in image) is perfectly noticeable this time.
Now, I don't note any sour taste or bad smell or the curd like solids in it. It seems fine to me.
But does this layer mean it has started to go sour and will rise eventually?