Chemicals in our food Discussion Page

Quick Links
LENScience Home
  Chemicals in our Food Teacher Page LENScience Connect Bookings and Registration

Chemicals in Our Food: Discussion Page

To ask questions and take part in any discussion you need a username and password for this wiki. If you don't have one, click on Log In/Create Account in the grey box on the left. Then choose Create Account. Enter a username and password of your choice. We also recommend that you enter your email address as well. Your wiki account needs to be approved before you can use it.

Guide to discussion
How to start editing
How to start editing

-Be polite
-Assume good faith
-No personal attacks
-Be welcoming

How to edit a wiki movie or if you are in a rush, there is the quick-edit movie. These show you how to contribute to this discussion page.

If you cannot open the movie, here are the instructions as a pdf file

Here is an example of how to write in this page:

South City High School Teacher Mary: 16th April 2pm - Can you please explain why................... 

Please put your school name and write the date and time - then ask your question

General Discussion

Put your questions here........


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 They were used extensively in cling films, but were withdrawn a few years ago because of the risks associated with their migration into food – they were replaced in cling films with adipates which are not estrogenic (but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!