Minnesota has been added to a long list of states — now numbering 45 — affected by an unusual beef recall stemming from the slaughter of "diseased and unsound" animals, according to federal regulators.

The recall of nearly 9 million pounds of beef products began in mid-February after the Rancho Feeding Corp. slaughterhouse in Northern California was closed. On Friday, 55 Minnesota retailers, many of them convenience stores or small supermarkets, were added to a list of affected outlets that nationally number over 5,000.

The stores sold "various beef products" connected to the Rancho recall, according to the U.S. Department of Agriculture website. Twin Cities-based Target and Supervalu have also been affected by the recall, which has not been connected to any reported illnesses nationwide.

The USDA's public declaration on the matter has been particularly blunt. Rancho Feeding carried out slaughtering activity without full federal inspection, which is required of all meat plants. Thus, affected products are "adulterated," because they are "unwholesome or otherwise unfit for human food," according to USDA.

"It's a little bizarre," said Ryan Osterholm, a food safety attorney at Pritzker Olsen in Minneapolis. " 'Diseased and unsound animals' isn't common language in recalls," he said. "The USDA is saying 'this is not OK,' and they are throwing the book at them."

Circumstances surrounding the recall are reportedly under criminal investigation. Also, the San Francisco Chronicle and the Los Angeles Times have reported that Rancho slaughtered some cows with eye cancer, a development not necessarily linked to any criminal or regulatory investigation.

The recall involved beef produced from Jan. 1, 2013, through Jan. 7, 2014, meat likely used in a multitude of processed foods. But by now, most of those products have likely been removed from store shelves or consumed, Osterholm said.

Because the beef was distributed to packaged-food companies, who used it in their products, there is no precise list at this point of items that might have included the recalled meat.

Last month, packaged food giant Nestlé recalled certain Hot Pockets brand sandwiches that had been made with Rancho products. Nestlé said it received a small quantity of Rancho's meat at its Chatsworth, Calif., plant that was ultimately used in some Hot Pockets Philly Cheese Steak items.

Hot Pockets affected by the recall were not distributed in Minnesota, said Hannah Coan, a Nestlé spokeswoman.

However, Target stores across much of the country were affected by the Hot Pockets recall. Target outlets were instructed to remove the products from store shelves, the company said in a statement.

Supervalu, too, was hit by the Hot Pocket recall, said company spokesman Jeff Swanson. Also, due to the Rancho beef recall, Supervalu recalled to its own distributors Wilmar brand ground beef patties, Farmer John's franks and El Monterey taquitos. Recalled products have been pulled from stores.

According to the USDA's website, Supervalu's Save-A-Lot stores in California and Cub Foods outlets in Illinois — but not Minnesota — were affected by the recall.

SuperAmerica convenience stores in Minnesota were also hit by the Rancho recall. Northern Tier Energy, the corporation that owns SuperAmerica, didn't return calls for comment Tuesday.

Mike Hughlett • 612-673-7003