Perhaps your Crested's cage(s) need a little better ventilation, that may help a bit. I've found that with my Crested's cages (mostly screen), although there's no mold on the baby food, it does dry up quite a bit overnight. So I just throw it away in the morning. I would suggest making sure you don't give your Crested's excessive baby food (there's a tendency to give too much baby food and it gets wasted) and change it each day. Just put it in at night and take it out in the morning.