She can be allergic to ascorbic acid. If she has been breastfed then this could be a sign she is allergic to corn. The reason that foods that she did not have problems with in the past are now causing her problems is that overtime (and exposure) one typically becomes more and more sensitive to the allergen. You don't mention if you are breast or bottle feeding and that's relevant. If you are bottle feeding, then she's already gotten boatloads of exposure to corn in the formula, so it's not likely a corn allergy. But, it could be an apple allergy. I am allergic to apples, peaches and quite a few other things and as I noted, she might have been okay with it before, but she may have become sensitized. As others have noted, making your own baby food and slowing down the introduction of solids are really good ideas. Solids should not be a significant source of nutrients for babies for their first year. Breastmilk and formula are actually all that a baby needs for the first full year - solids are just to get them used to the idea of eating table foods. For my sons we skipped the jarred food altogether and just gave them small amounts of whatever we were eating that was appropriate (mashed potatoes, rice, mashed peas, mashed sweet potato, etc.) and gradually over time they were eating just what we were for dinner. My younger son, who we later learned had food allergies, ate very little solids until he was 9 months old. There really is no rush at all for solids.