It said if the scheme is successful it could be extended locally but wherever possible unsold good food would continue to be donated to worthy causes.
Ferndown branch has secured a contract with organics recycling firm Eco Composting (Eco) to handle its waste food on a trial basis.
Collection will take place at least once every fortnight and taken to Ecos 14-acre site at nearby Parley to be treated under EU Category 3 standards.
The facility is one of only a few in the country able to conduct this process, which includes heating to 70°C.
Sainsburys recycling and resources manager James McKechnie said: A rising landfill tax, and a growing expectation that we must get better at dealing with waste, means that we are just starting to see businesses such as Sainsburys link to local composting companies like Eco.
Ecos sales and marketing director Andy Hill said the company considered the recycling of food waste as a major growth area.
Compost resulting from the treatment process rests for up to four months and is then screened for plastics and other materials before being used to grow turf.
Sainsburys has 562 sites across the UK and has been trialling a similar scheme in 21 of its stores across east and South East London.