The color change is due to natural colorants, like carotene. This colorant can be found in carrots, tomatoes, pumpkins and many other fruits and vegetables. Although the change in color can be drastic, it is not harmful and does not have any taste or odor.  Nuby spoons are made to be comfortable and safe for your baby. The soft tip and heat sensitive features common in many of our spoons are only possible using materials that are somewhat susceptible to natural colorants.  It is possible to produce the spoons with a different material that does not discolor, but it would not be able to function the same and thus, would not be as comfortable or as safe for your baby.  To help avoid the color change for bottles, clean them carefully with warm water and a mild detergent before sterilizing.  It is also helpful to not clean them using the dishwasher.