St-Hyacinthe, Que., is on its way to becoming the first municipality in the province to convert yogurt into natural gas.

An agreement between the town of 50,000 located 60 kilometres east of Montreal and Yoplait Liberté will see substandard and expired yogurt sent to the town's biomethane plant for conversion to natural gas.

The plant is already producing natural gas from organic matter collected through composting programs from 23 neighbouring municipalities.

The waste yogurt will be heated at 37.5 C for 26 days.

"Methanogens do the rest," said Stéphane Pedneault, the production supervisor at the plant.

Methanogens are microorganisms that convert organic matter to methane.

The natural gas produced will be used to power the municipality's vehicles and heat its buildings.

The surplus gas produced, which could total 13 million cubic metres per year, will be sold to the Gaz Métropolitain utility.

The project has cost $50 million so far, of which two-thirds has come from provincial and municipal governments.

The municipality is hoping to establish similar agreements with other companies in the agri-food sector.