She got worried about the news regarding dangers with baby feeding bottles. The migration of Bisphenol A substance to baby milk formula. The feeding bottles in question are those with number 7 recycling symbols or polycarbonates.
update as of June 19, 2016:
Low level BPA exposure is safe according to FDA. See “FDA Approved Number 7 Juice Bottle ?”
We noticed that most of our baby’s feeding bottles have recycling code of number 7. Some of them have recycling code of number 5 and some have no recycling symbol. We started to avoid those with code 7 and no code bottles. Identity of no code bottles is unknown. Its not safe to gamble with unknown bottles?
Through research, I discovered the recycling symbol number 5 is polypropylene. A plastic polymer that is widely used for food industry. Unlike polycarbonate and other plastics, it is resistant to heat with a melting point of 160° Centigrade. Water boiling temperature of 100° C has no affect on this plastic. It is popular for its resistance to chemical solvents, bases and acids.
Food applications of polypropylene containers are yogurt packages, syrup bottles, ketchup bottles, caps, straws, medicine bottles and other hot-packed food products.
Plus no reported health issues about polypropylene. So we decided to replace all our baby feeding bottles with this kind of plastic.
In buying feeding bottles, we always look for the number 5 recycling code. Polypropylene is also softer than polycarbonate.