Chemicals in our food Discussion Page

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Chemicals in Our Food: Discussion Page

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Dr. Simon G. McMillan, Kaikorai Valley College, 22nd November

  1. Most of our water bottles beverages in NZ I think are in PET bottles not polycarbonate. Do they also have BPA in them?
  2. Are the phthalates also an issue?
  3. What is the reason the BPA is used in the laced polymer to line the cans of preserved tin goods?

Ian Shaw 22nd November

  1. Yes most water bottles are PET and do not have BPA in them. The heavier bottles used for office water dispensers are polycarbonate.
  2. Phthalates are an issue – they are estrogenic AND inhibit the cellular synthesis of testosterone (a feminising double whammy!). They are very widely used and contaminate much of our world. They were used extensively in cling films, but were withdrawn a few years ago because of the risks associated with their migration into food – they were replaced in cling films with adipates which are not estrogenic (but still migrate.
  3. BPA lacquers are used to line tin cans to prevent the metal of the tin dissolving in the canned food. Acid foods are more of a problem which is why they are usually lacquered. Interestingly the BPA lining was first introduced when the seams of tins were lead soldered - the reasons are obvious – Pb is no longer used. I often wonder whether the risk of BPA in food is greater than a bit of Fe from the can!