Actually I can somewhat understand why a shelter wouldn't want to take open bags of food if they don't know you, unfortunately there are some sick people out there, and honestly they don't know what someone may have done to an open bag. I've never heard of that kind of food.....maybe a neighbor or friend or someone you know may be able to use it? I'm not real familiar with Mainstay but I think it's a pretty good brand, isn't it? I could be wrong though. Why did you switch? Just out of curiosity.