The supermarkets' much publicized supportive action is aimed at curbing cattle farms that have sprung up in Brazil's endangered rainforest, increasing the risk of deforestation.
Critics of the rain forest industrial development say powerful vested interests are baring vast Amazonian nature reserves with impunity and setting up cattle ranches and other production facilities.
Typical of Brazil's lopsided law enforcement, as evidenced in continued existence of huge favela slum settlements in urban centers including Rio de Janeiro, business interests continue to cut down the jungle and build factories for meat and other farm produce.
The 2,800-member Brazilian Association of Supermarkets announced it would no longer sell meat from cattle raised on land that until recently was part of the rainforest.
However, the grocers' pledge to ban the produce stopped short of setting deadlines or outlining key governance issues over enforcement and punitive measures against potential defaulters.
The announcement raised skepticism that the proposed ban would sooner fall by the wayside than be implemented in earnest by the supermarket chains.
Despite legal bans, thousands of hectares of forested areas in the Amazonian basin are being laid waste and lucrative agricultural projects are being installed on the affected land.
Critics said that meat production was one of several incursions into the rainforest. Large tracts of Amazonian territory has been converted into farms for livestock, energy feedstock, soybean production and other activities -- all illegal and yet carried on with impunity.
The supermarkets' pledge came as part of an initiative by the Public Prosecutor's Office to deprive the meat producers of outlets. It's an uphill struggle and victory for the law enforcement agencies is far from certain, industry analysts said.
Prosecutor's Office sources said in news media reports the supermarkets promised to take specific measures to inform consumers about the origins of the meat.
Critics said the practice is well known and the supply of Amazon meat products has created demand that may continue to exist even if the supermarkets stop selling the meat products.
An Internet campaign aimed at informing Brazilian consumers of the ethics of boycotting meat from Amazonian sources is also planned.
A more transparent labeling system that will clearly identify the meat's origins is part of the plan. But critics point out that enforcement is the key. Both the government and the supermarkets will need to develop an infrastructure to implement the ban.
Officials say the new measures will make it harder for shops to sell items from producers who flout the law. In the next step, the government intends to extend the campaigner to smaller grocers.
Officials said they would work toward reaching a similar deal with smaller shops.
Brazil's Greenpeace advocacy group says the growth of the cattle industry in the Amazon is the single biggest cause of deforestation. For decades now, Brazilian authorities have battled illegal logging and other activities that continue to reduce the rainforest.
In January the Brazilian government announced it plans to prepare an inventory of the trees in the Amazon rainforest.
The Forestry Ministry said the census would take four years to complete and would provide detailed data on tree species, soils and biodiversity in the world's largest rainforest.
The last such exhaustive survey was conducted more than three decades ago but didn't help stop deforestation.