As long as you have already introduced your baby to the allergens found in our products, you can feel free to use Ready. Set. Food! Stages 2 and 3 Mix-Ins, Organic Baby Oatmeal, or our Organic Oat & Fruit Bars on the same day to maintain the exposure. If you have not introduced allergens, it is recommended to start with Stage 1 Mix-Ins first before expanding exposure to other allergens with our other products.