About 120 kids did get to sample the stuff, but they also learned how cocoa is grown and harvested, and how buying chocolate with the Fairtrade logo helps improve the lives of people in poor countries.

Living proof was Esther Ephraim, a cocoa farmer from Ghana in west Africa, who told the children, aged 11 to 15, that a premium that buyers pay to producers under fair trade rules enabled her community to build a well.

Previously, they drank from a river that people also bathed in, leading to water-borne diseases.

Ms Ephraim, 28, said her family joined the Kuapa Kokoo Co-operative, a group of 65,000 farmers operating under fair trade, because a minimum price is set for their product to provide a good income, and the premium gave them free cutlasses, medical clinic, training and better education for children.

Women were encouraged to be managers, and decisions were made democratically.

As part of Fair Trade Fortnight, on until May 18, Fairtrade Australia launched a campaign to educate families about the impact their choice of Fairtrade tea, coffee and cocoa brands can have on farmers in developing countries.

Valentina Tripp, chair of Fairtrade Australia, said 1.3 million farmers in 70 countries now worked under fair trade conditions and premiums had invested $120 million into community development projects.

People keen to buy ethically should look for the Fairtrade logo on products, or view a list of brands on the Fairtrade website. She called on the public to ask for Fairtrade products at shops and write to politicians ‘‘to start to bring more fair trade products on to our shelves’’.

At present in Australia less than 5 per cent of chocolate on sale is certified Fairtrade.

She said 150 Australian schools have pledged to buy fair trade items such as tea, coffee, school bags, soccer balls and even uniforms.

Will Slupecki, 11, was fascinated by Ms Ephraim’s slide presentation on how cocoa grew in trees, in pods that were cut down. The seeds were picked out and dried, then put into sacks for market. And he now knows where Ghana is.

‘‘I thought there wasn’t much effort put into chocolate, but seeing that PowerPoint I found out there’s lots of effort put into one piece of chocolate.’’

Will said he now saw how buying Fairtrade chocolate might make a difference for workers, ‘‘because they would get a premium that could improve their lives for getting more running water and clothes and schools’’.

Ms Ephraim urged Australians to continue to advocate for Fairtrade, ‘‘because we are getting so many benefits from Fairtrade, and it is helping us a lot. We want more to improve, so kindly do what you can to contribute to help us. Thank you’’.