The tiny state of Vermont has taken on the entire US food industry to force many manufacturers to label products containing genetically-modified ingredients - or GMs.

The law takes effect on 1 July, in a state where many consumers are wary of scientifically-altered products. That will have an effect across the country.

But food companies maintain that such foods are proven to be safe to eat, and don't harm the environment.

Jane O'Brien travelled to Vermont to learn more about the GM food fight.

Filmed by Colm O'Molloy, edited by Bill McKenna.

Produced by Sarah McHaney.