You know organic has truly gone mainstream when a conventional supermarket chain launches its own store brand. I’m talking about Stop & Shop’s “Nature’s Promise a line of “natural and organic foods” which the multibillion-dollar corporation, with more than 360 stores in New England, New York, and New Jersey, launched last October. Stop & Shop is promoting its Nature’s Promise brand with the slogan “Wallet-Friendly Organics.”

I just discovered the Nature’s Promise line yesterday when I went to restock my upstate pantry with basics such as chicken broth. Previously, I had two choices if I wanted to cook with organic chicken broth: I could pay nearly $4 for a quart of Pacific or Imagine at Stop & Shop, or I could schlep quarts of Whole Foods’ own brand, which costs $1.99, on the train to our Hudson Valley hamlet.

The schlepping gets pretty tiresome when you’re already hauling several laptops, a twelve pound calico, and all the other weekend essentials. So when I spotted the quarts of Nature’s Promise organic chicken broth, for only $2.09, I was pretty excited. If this stuff is any good, our days of schlepping may be over. I bought a quart, put it in the pantry, and plan to try it soon, maybe next weekend.

But can you trust a conventional supermarket chain to really be organic? As I noted last week, Wal-Mart is now the nation’s largest seller of organic milk. But Horizon, the vendor who supplies Wal-Mart’s organic dairy products, is suspected of violating USDA regulations by failing to uphold organic standards.

Shareholders of Horizon’s parent company, Dean Foods, are so concerned about the growing criticism of Horizon from consumer watchdog groups and the media that they’ve filed a shareholder proposal demanding a response to the allegations. Shareholders fear all the negative publicity will damage the value of the Horizon brand, which some retailers have dropped in light of the controversy.

Stop & Shop’s stated goal in launching Nature’s Promise is to make natural and organic foods “more easily accessible to everyone.” Anticipating skepticism from consumers, Stop & Shop’s website says, “Why trust Nature’s Promise? Because we follow strict quality standards for every item and organic certification requirements…and we’ll never stop adhering to them.”

But how rigorously does the USDA monitor compliance with organic standards? We’re talking about an agency that allowed tainted meat to sit on store shelves for months without notifying the public or recalling the potentially toxic product. Can we really count on them to ensure that manufacturers of foods bearing the “USDA organic” label meet all the federally established standards?

We may find some answers in an about-to-be-published book by Samuel Fromartz, Organic, Inc.: Natural Foods and How They Grew, which chronicles the rise of the organic food business from a niche market to one of the fastest growing segments of the food industry. Fromartz, a business journalist, delves into the backgrounds of companies like Whole Foods and Earthbound Farm, and the corporations like Kraft and General Mills who’ve cornered the bulk of the organic market, according to Formartz.

Committed consumers of organics are an educated and affluent bunch, which makes us kind of a double-edged sword for marketers; yes, we’re willing to spend more for healthier, more environmentally friendly products, but we also read the fine print, and we’re acutely aware of the phenomenon known as ”greenwashing whereby cynical corporations adopt a “green” veneer in order to woo us.

Scratch that green patina, though, and you’ll see just how shallow some corporations’ commitments are to providing socially responsible consumer products. Nature’s Promise sounds, well, promising, as the marketers who dreamed it up no doubt intended, but will they keep their word and uphold organic standards? There may be a cloud over Horizon, but maybe Nature’s Promise will really deliver. I hope so. Trust but verify, as the Gipper said.