Yes, but you have to make sure both milks with same temp. i.e. you have to put 下午泵出來的奶 into the 雪櫃 for at least 1 hour till it is cold. Then you can mix it with 上午泵出來的奶.
Make sure that those milk will be used within 2 days if you stored it in the 雪櫃 .
If your baby cannot consume it within 2 days, you have to put it into the freezer within 10 hours.