The UK retailer said the move will cut 3,550 tonnes of plastic used on about 500 of its private label products and reduce rubbish collected for landfill. The conversion will Sainsbury's ready meals and organic food products, which use about 150 million plastic trays and bags each year.
Over the past two years packaging suppliers have been introducing various forms of biodegradable plastics made from a variety of plants, in the main corn, based on projections that there will be a growing demand for environmentally-friendly packaging driven by consumers and recycling regulations.
Some companies predict that the market will grow by about 20 per cent a year, as an alternative to petroleum-based packaging such as the widely-used polyethylene terephthalate (PET).
Sainsbury's will replace the plastic packaging used for those products with ones made out of maize, sugar-cane or starch. Such packaging materials, which have been appearing on the market for use by food companies, naturally break down in a garden compost heap, eradicating the need for packaging to be binned or bagged and sent to landfill.
In making the announcement on Friday, Justin King, Sainsbury's chief executive, called on government to ensure that every home in the UK has a compost bin. He also challenged other retailers to follow suit so as to make compostable packaging a norm in the UK.
King said that in some cases, for example organic tomatoes, everything can be composted at home - from the film and tray that keeps the tomatoes from being damaged, to the vines. He says the company's tests show that compostable packaging will break down quicker than a banana skin, yet it takes many years for degradable packaging or carrier bags to do the same.
Degradable plastic is made from oil a fossil fuel with additives to enable it to break down to CO2 plus water. The process typically takes two years to complete. Compostable or biodegradable plastic is usually made from plant based starch that breaks down into CO2 and water.
Under Sainsbury's plan about 50 per cent of organic fruit and vegetables will be available in compostable packaging from this week. The share will jump to 80 per cent by January 2007. By Sept 2007, Sainsbury's plans to complete converting all the packaging on its ready meals. Organic sausages and organic whole bird will be converted by October 2007.
Sainsbury's has also produced packaging guidelines for its suppliers so that more food is packaged in compostable or recyclable material. From this month, Sainsbury's will also be making packaging guidelines clearer on food labels.
Sainsbury's pioneered using compostable packaging in 2002. It claims to be the single largest user of compostable packaging in Europe.
Before September 2006, Sainsbury's had been trialling fully compostable, wrap on a number of its organic produce lines. The trials included converting the packaging for apples and potatoes.
The company is using a variety of companies for its compostable packaging. This includes the use of: compostable sugar cane trays, and the use of polylactic acid (PLA) packaging for punnets or pallets. PLA is a corn-based biodegradable polymer made by US-based NatureWorks. The PLA supplier is part of Cargill and is one the main movers behind the biodegradable packaging trend.
Sainsbury said it is the only retailer to require that NatureWorks supplies it with PLA that is free of genetically modified ingredients. PLA has held appeal within the packaging industry because it is biodegradable when composted, helping food packagers to meet EU waste targets.
Where Sainsbury's cannot use compostable material, it will use a recyclable version, the company stated.
Sainsbury's move follows that of Belgium-based supermarket Delhaize. Earlier this year the retailer said it would adopt biodegradable packaging for prepared salads.
Delhaize has been testing NatureWorks' corn-based packaging since August 2005 in one store. Now the chain calls the trials "successful", all Delhaize supermarkets in Belgium will be using the packaging for prepared salads.
The mandate extends to external suppliers -- as well as organic and traditional bread sold in the stores.