Anya was the overall winner of the school's annual science fair competition with her project.
"I saw the (Anchor) advert with the see-through cows on TV and thought well, does it actually work?" she said.
"I was pretty surprised when it turned out it didn't."
Anya placed the three bottles, each containing one litre of full cream milk, in a box with a UV light.
Anya rotated the bottles on a regular basis to ensure equal light exposure.
Science teacher Ann-Marie Beazley said she was not surprised at the findings as she was a "bit of a sceptic" of the company's claim.
"There was a lot of attention generated around her board at the presentations, with people commenting about the ridiculous price of milk and how you can never tell how much is left in the lightproof bottle," Miss Beazley said.
But Anchor group marketing manager Craig Irwin said by leaving the milk out of the fridge, Anya had actually tested the effect of storage temperature on the quality of milk.
"Milk has two enemies, heat and light," he said.
"The Anchor light-proof bottle protects milk from light, but it does not prevent heat damage or 'temperature abuse' ... all milk requires refrigeration."
Pompallier's head of science Michael Pohlenz said Anya did a "stellar" job.
"She controlled everything she could control, and measured everything she could measure.
"She was very thorough," Mr Pohlenz said.
"I was surprised at the results. Obviously she can't test all of the biology, all of the microbes that form, so there is the possibility the light-proof one may be better, but at a Year 9 level it's proved not the case."
What do you think?
Email: letters@northernadvocate.co.nz