The fast-casual restaurant with food made with humanely-treated and environmentally-friendly ingredients may be forced to ease some of its beef requirements as beef supplies deplete.

Tight beef supply may force Chipotle to change standardsThe beef used by Chipotle in its Food With Integrity program requires that products from its suppliers meet the company’s naturally raised standards. The Chipotle website says the beef served by the chain was raised without the use of antibiotics or added hormones.

With cattle numbers falling to a 60-year low, Chipotle is having a hard time purchasing beef meeting its requirements. Almost all of the beef used by the restaurant last year met its guidelines, however Bloomberg reports between 80 percent and 85 percent of the beef used by the burrito chain this year meet those same requirements.

Shrinking beef supplies are forcing the restaurant to reconsider its standards. Bloomberg reports Chipotle is considering lighter restrictions to allow beef from cattle treated with antibiotics to recover from an illness. The company would still reject beef from cattle given antibiotics to promote weight gain or prevent disease.

A release from Chipotle says the company's protocol allows the use of antibiotics to treat sick animals, but those animals are removed from Chipotle's food supply. The company is considering whether it should change its "never-ever" protocol, allowing treated animals to remain in the herd.

Chipotle spokesman Chris Arnold says the company increases ingredient purchases by 20 to 25 percent every year to keep up with increasing sales. He told Businessweek the beef supply hasn’t been able to keep up with the company’s growth.

The company is considering alternative options, including purchasing from new suppliers andadding other cuts of beef.