With hot weather, milk can go bad easily on long shopping trips. Here are five things to look for to see if your milk has gone bad.
#1 Smell It
One obvious way to tell if your milk has gone bad is to smell it. If it smells sour, it has more than likely gone bad.
When milk has gone bad, it sometimes changes color. Obvious changes in color will be some yellow, light blue, or reddish. 
When cottage cheese comes out of your milk container, that is a sign that your milk has gone bad. Bad milk will have lumps in it.
#4 Sour Flavor
This goes in conjunction with number one. If you don’t have a good nose, you can taste the milk. Just take a little sip of the milk and if it tastes sour, dump it out.
If you’re worried that your milk is bad, try these tests to see if it actually bad.