I think there was an earlier thread relating to this very thing. I cannot remember all of the things which were noted. From what I remember, I think tomatoes were mentioned as one of the items that do not do well when stored in the fridge. They tend to become soft overtime. So even if they are ripe, the fridge would not preserve them and they would do better outside of the fridge. Where table butter is concerned, I always store this in the fridge and have not gotten any bad results from doing so. If I keep table butter out of the refrigerator for too long, it becomes very soft and gets runny. However, margarine does well out of the fridge. If I cut an onion and leave a portion of it in the fridge for a few days, it starts to get brown, so I would have to use it up before it gets to that stage. This is the first time I am hearing that it becomes toxic. I don't know if turning brown means that it has reached the toxic stage.