The financial damage to North Bay ranchers — many of them raising high-end, grass-fed beef — makes the Rancho case rare among meat recalls, experts said. And to date no one has revealed such potentially huge losses as the Nimans.

The Bolinas couple, who started BN Ranch in 2007, said their company's freezers contain nearly 100,000 pounds of pasture-raised meats, none of which currently can be sold. That amounts to more than a quarter of all the meat they processed last year at Rancho.

BN customers have returned another $40,000 worth of meat that can't be resold. Niman said a Rancho owner told him the slaughterhouse isn't liable for that loss.

"We're the ones taking a big hit on this," said Niman, 69, who also founded Niman Ranch in the early 1970s and is widely considered one of the early leaders in humane and sustainable meat production. He since has severed ties with the Alameda-based meat company that still bears his name.

The couple said the losses may put them out of business. They have asked the U.S. Department of Agriculture to review documents showing that BN managers or Niman himself were at Rancho with USDA inspectors every time their animals were killed and processed.

"We not only know the inspectors were there," said Nicolette Hahn Niman. "We were there ourselves."

The USDA has asserted that Rancho "processed diseased animals" without a full inspection. The department this week added that it is investigating "the company's intermittent circumvention of inspection requirements."

A Rancho owner has denied the latter allegation and said the company never harvested animals without an inspector on site.

Two different USDA offices are investigating the company. The department has not received any reports of illness linked to the meat.

Rancho has ceased operations and is now recalling all 8.7 million pounds of meat processed last year at the plant on Petaluma Boulevard North. Marin Sun Farms, a gourmet farm-to-table meat producer, is buying the plant and hopes to reopen it soon, possibly within two months.

The recall has touched more than 1,600 establishments across the country, moving beyond local markets and custom meat purveyors to national grocery chains. The recalled products range from Hot Pockets frozen sandwiches and taquitos to high-end porterhouse steaks like the ones sold under BN brand, which might cost $19 to $20 a pound in a butcher's shop.

Nicolette Hahn Niman, a former environmental attorney, acknowledged that her husband is "a maniac" when it comes to tracking his livestock. He does so to ensure the animals are humanely treated throughout their lives, to measure which cattle have the best genetics and to make sure the meat is safe.

"We don't drop our animals off at a slaughterhouse and hope it works out for the best," Niman said.

He said he has logs documenting that BN Ranch made sure its animals never got near any other cattle at Rancho. And he dismissed as "very slim" the possibility that BN's carcasses would ever have been touched by any suspect meat. The custom-killed animals are hung on a different track, or rail, from Rancho's own cattle when they are moved to cold storage.

Unlike some grass-fed producers, BN Ranch doesn't harvest cattle in the winter, when the grass lacks the nutrients Niman demands for his cattle. He typically has the animals slaughtered from May to October and freezes a large portion of the meat for distribution throughout the year.

Robert Singleton, one of Rancho's owners, said in an interview Thursday that the Nimans' meat is safe and it never came in contact with any of Rancho's own beef.

"They were never commingled," Singleton said.

Rep. Jared Huffman, D-San Rafael, said Friday that the Nimans "go above and beyond any existing standards" in their operations. The USDA should test the meat or find some other way to ensure its safety and prevent its destruction.

"I'm going to try to push in every way I can to get them to try to do that," Huffman said.

He said the department's investigation is causing regulators "paralysis" and "visiting damage on my constituents."

"I just think the USDA needs to step up here and help out ranchers like the Nimans," he said.

A USDA spokesman said the department is aware of the concerns of the Nimans and other producers but could make no further comment due to its investigation.

Nicolette Hahn Niman said the couple has spoken to "several high-level officials" with the USDA who seem genuinely concerned.

John Munsell, a former meat plant owner and a consultant in Miles City, Mont., said what makes the Rancho case unusual is that so many ranchers are using the plant for custom slaughter and keeping the meat for their own sales and distribution.

"Most recalls are for products that were all commingled together," he said. Typically, the processing facility, not the ranchers, owns all the meat that gets taken back and destroyed.

"This is a pretty unique situation," Munsell said.

Niman said he is confident his meat is safe and the thought of dumping so much of it into a landfill is "abhorrent and immoral."

Should that day come, he said, "it would be one of the toughest moments of my life."