When to start citrus?

I remembered reading that you shouldn't give any citrus foods to infants until they are 12 months old, but I wasn't sure why, so I looked it up. One source Super Baby Foods said to wait until 12 months because oranges are a common allergen (437). The Well-Fed Baby said to give citrus foods to infants over 10 months old. The Blender Baby Food book has recipes that call for 1/2 cup of orange juice in them: one recipe (58) meant for six month olds has a note that says to substitute water for stomachs irritated by citrus, but recipes on page 72 (for 6 months) and page 118 (for 8 months) do not say anything about the orange juice ingredient. The Homemade Baby Food book says you should wait until the baby is over 12 months old for tomatoes and orange juice because of digestion. I have heard that it is harder for kidneys to digest oranges, but that didn't come from a book or a doctor.

In conclusion, whether it's for allergies or digestion, I would wait 12 months. I do wonder about foods (including processed infant foods) that include citric acid as an ingredient. My guess is that it's such a small amount that it won't matter too much.