Minuscule rash after introducing first solid food?

[Miss]

So I gave my daughter her first taste of solid food yesterday morning and I thought it was successful. She ate and swallowed very well and thoroughly enjoyed the experience. Throughout the day I watched her for any allergic reaction and noticed nothing. But at the next diaper change after her first bowel movement since having the solid food I noticed some redness around her anus and a small amount of red splotches on her bottom. The rash cleared up by this morning without any diaper cream or special treatment. Are minor rashes common when starting new foods? I gave her Beech Nut banana baby food. Her doctor said that rather than cereal I could start her with either bananas, avocado, sweet potatoes, or pears. I also read the ingredients and was thinking that maybe it was the citric or ascorbic acid? Help! Let me hear your motherly experiences!

Also, she has been breastfed exclusively up until this point.