Basta kung hindi po ilalagay sa ref at room temperature lang, upto 4 hrs or less lang bago mapanis (mas mabilis kung mainit panahon). kung ihahalo nyo po yung bagong pump, yung shelf life ng 1st batch ang iaasume nyo. so let's say 1st batch was pumped at 4pm, inihalo ang 2nd pump at 6pm, then until 8pm lng yun pareho.
Also kung maghahalo ng breastmilk, dapat ay same temperature sila. So let's say nilagay nyo sa ref yung 1st batch, dapat palamigin rin muna sa ref yung 2nd batch bago paghaluin.