Excellent question. What your describing is likely something called lenticels. This is a naturally occurring characteristic found on the skins  of many fruits and vegetables. Consider, potatoes are technically a living organism. The Lenticels are tiny breathing pores that allow oxygen and carbon dioxide (natural gas exchanges necessary for plant organisms). Lenticels may be more or less visible, depending on the produce item and variety. For example, next time you’re in the produce department take a close look at the surface of  a golden delicious apple. The lighter skin provides an enhanced  view of the same, pinhead black  lenticel spots. Again, a naturally occurring characteristic, some produce having more visible lenticels than others, and something that has no effect on quality, flavor, nutrition or texture.  

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