Storing in plastic food bins isn't good. The plastic will leach nutrients and the oils in the food will get in the plastic and cause problems, it will start to smell like rancid oil.
Dang, just when you think you've got the food stuff down, you go and learn you're not doing it right. I suppose I can go back to my old method, which was to use a medium-sized steel ash can with the full bag of food inside it. The plastic container just fit so much better in the pantry. Figures!
As for the mold in the food, the most troublesome thing is that I would hardly have noticed it except that I have been supplementing Reba's food with oils and glucosamine and all these other things lately . . . otherwise, I would have scooped and figured it was just some pulverized grain. but nope, I picked up the dish and it was most definitely moldy.
Gross. I hope nobody's Canidae eating pup gets sick. I WILL be sending them a note, even though I haven't retained my proof of purchase.