We had this horrible smell in my cupboard and it seemed like it was coming from the plastic bag on the bread. I took out the loaf I thought was the offending one and it still smelled bad in the cupboard, but after a day the plastic on that loaf of bread didn't smell. But, the plastic on the other loafs in the cupboard (various breads for various people) smelled. So, I thought it came from the store. We shopped at a store we don't normally shop at. But, after a day out of the cupboard, bread packaging smelled normal, but the cupboard still smelled horrible. Now, I have a very sensitive sense of smell. It gave me a headache just to open the cupboard. It's a double cupboard. It contains canned goods, spices and breads, so I couldn't figure out what could be causing it. So, I started to take everything out, and on the top shelf, in the very back where I can't see AND behind the spices was a rather old, rather green package of hamburger buns. I now have a bowl of baking soda in the cupboard hoping to get rid of the smell. I always loved opening that cupboard because it smelled good. Obviously, the previous owner kept her spices in there, too. This is what happens when kids put groceries away and just shove things in.