More than 6 million eggs sold under the Black Sheep Egg Company brand have been recalled after federal officials detected multiple strains of salmonella at one of its processing facilities.

The U.S. Food and Drug Administration (FDA) announced the recall after 40 environmental samples tested positive for salmonella, including seven strains known to cause human illness.

This recall could "cause serious adverse health consequences or death," the agency said.

The contaminated eggs came from Black Sheep Egg Company’s Arkansas processing plant and were distributed to retailers and food suppliers in Arkansas, Missouri and potentially other states, CNET reported.

The recall includes several 12- and 18-count cartons of Black Sheep Egg Company Free Range Large Grade A Brown Eggs with Best By dates between Aug. 7 and Oct. 31 or UPC codes 860010568507 and 860010568538.

Other affected products include:

• Free Range Grade AA Large and Medium Brown Eggs (loose-packed in boxes or open skids)

• Free Range Grade AA Large and Medium White Eggs (loose-packed or in cartons)

In addition, Kenz Henz, a Texas-based supplier using Black Sheep eggs, recalled its Grade AA Large Pasture Raised Eggs (12-count cartons) with Best By dates between Oct. 11 and Oct. 17 and UPC code 86949400030.

Although no illnesses have been reported, officials warned that salmonella can spread quickly through contaminated food and surfaces.

Black Sheep Egg Company said it is cooperating fully with the FDA.

Consumers are urged to immediately throw away or return any recalled products. The FDA also recommends washing and sanitizing any surfaces or utensils that may have come into contact with the eggs.

People who have eaten the recalled eggs should monitor for symptoms of salmonella, which can include fever, diarrhea and abdominal cramps appearing 12 to 72 hours after exposure.

"Children younger than 5, the elderly and people with weakened immune systems are more likely to have severe infections," the agency added.