This mimics the feeding behaviors of parrots in the wild. We have observed them many times feeding in the wild. Surely some bacteria does grow in food over the course of hours but this is not a problem. Bacteria are normal gut flora and if the bird has a healthy immune system, it can handle a small amount of bacteria with no problem whatsoever. We do not have problems with bacteria as a primary health problem here.
Bacterial overgrowth is generally secondary to another health problem.
Please do not think we are saying that pellets are bad foods. We just think they are fed instead of fresh foods way too much.