Unused breast milk question

Couldn’t really find anything online for this scenario so I thought I’d get some opinions.

I’m pumping between feedings so dad can participate as well.

Took two ounces out of the fridge this morning and put it in a clean bottle and then into our Phillips Avent bottle warmer. By the time it was done baby had fallen back asleep and has been asleep for about an hour.

Do I just need to discard this now or can I put the bottle in the fridge for later use? He never drank from the bottle at all.