No-drip Sippy Cup Mildew
While taking apart a no-drip sippy cup that included a straw, I happened to look into the hole where the straw fit. I was amazed at the black gunk-mildew that had formed there!
I also noticed mildew on the soft rubber "no-drip" attachment of another sippy cup. I am EXTREMELY vigilant about keeping my grandson's cups, etc. clean, so this mildew had formed quickly. I immediately pitched the cups.
We also saw that a baby bottle brought in by a parent in our church nursery had mildew around the flat part of the nipple that fits under the ring that screws onto the top of the bottle and holds the nipple in. Apparently, she was washing the bottle, but not removing the nipple from the ring.
This mildew may not be the most horrific thing that can get onto a child's drinking utensils, but some children have allergies to mold and mildew; plus, it's just plain nasty! Be sure to check closely when you wash sippy cups and be sure to remove the nipple from the ring when you wash bottles!
Every couple of weeks i soak all my DD's sippy cups/straws/covers and all attachments in bleach. Not straight bleach its about a 1-3. I find that keeps the black stuff from building.
Yes I have noticed with some our sippy cups if you do not take apart the white plug from the lid it will also get the wonderful yucky black substance. If I cannot get it clean then it is time to throw it away.