Issued this week by agricultural policy research group Cornucopia Institute, the study was based on responses to a survey sent out to organic dairy farmers.
The report, which rates 68 different organic dairy brands, accuses a handful of "industrial-scale" farms of compromising organic standards through "unethical" production practices with 2000-6000 animals in factory-farm conditions.
The Cornucopia Institute, which supports family-scale farmers, makes particular mention of leading organic milk brand Horizon Organic, owned by Dean Foods, as well as Aurora Organic Dairy.
But the industry is not accepting the attack in silence.
According to the nation's Organic Trade Association (OTA), the manner in which information was gathered for the report was "not scientific," and results may therefore be misleading.
The OTA has expressed particular concern over a sentence in the covering letter sent along with Cornucopia's survey, which states that "any firm(s) not participating will be indicated in the survey results, and that will likely taint the credibility of the organization(s)."
According to the OTA, "this type of threat is counter to good research practice, and renders the results invalid. Furthermore, such tactics do not serve the interests of customers, the organic community or farmers themselves."
But Cornucopia says the report "is a by-product of a five-year controversy that has been smoldering within the organic industry," and has accused the OTA of "backroom dealings" that have weakened federal organic regulations to the benefit of large corporations.
Entitled Maintaining the Integrity of Organic Milk, Cornucopia claims its report "will empower consumers and wholesale buyers who want to invest their food dollars to protect hard-working family farmers who are in danger of being washed off the land by a tidal wave of organic milk from these factory mega-farms."
But according to lead author of the report Mark Kastel, it is not all bad news.
"The vast majority of all name-brand organic dairy products are produced from milk from farms that follow accepted legal and ethical standards."
He also points out, however, that almost 20 percent of the brands now available on grocery shelves scored the substandard rating in the survey.
"This is not a debate of small farmers versus big farmers. It's ethical farmers versus farmers that are willing to compensate the ethics of organic farming," Kastel told FoodNavigator-USA.com.
"Some farmers are going to extra effort, many have lower herd production because of organic constraints, and they are placed at a competitive disadvantage," he added.
"We hope this report, and our web-based rating tool, will help organic consumers to 'vote in the marketplace' for brands that truly represent organic ethics, not just marketing hype."