By HEATHER HOLLINGSWORTH

KANSAS CITY, Mo. (AP) — A Las Vegas-based company and its owners have pleaded guilty to distributing a tainted ingredient used to make pet food that killed potentially thousands of dogs and cats.

Sally Qing Miller, 43, and her husband, Stephen S. Miller, 56, along with their company, Chemnutra Inc., pleaded guilty Tuesday to one count of selling adulterated food and one count of selling misbranded food, both misdemeanors.

They initially were charged with 13 counts of introduction of adulterated food into interstate commerce, 13 counts of introduction of misbranded food into interstate commerce and one felony count of conspiracy to commit wire fraud.

The charges were contained in a February 2008 federal indictment that alleged the Millers and ChemNutra, along with two Chinese companies, brought wheat gluten tainted with the chemical melamine into the U.S. It was then sold to pet-food makers, and thousands of cats and dogs reportedly became sickened or died.

In 2007, the case resulted in a nationwide recall of more than 150 brands of pet food.

"The conduct of these defendants in violating federal health and safety standards caused the deaths and illness of thousands of family pets, as well as anxiety among dog and cat owners across the country and economic harm to many pet food manufacturers," Acting U.S. Attorney Matt J. Whitworth said in a news release.

The sentencing hearing has not been scheduled. The Millers face up to two years in federal prison without parole, plus a fine up to $200,000 and an order of restitution. ChemNutra is subject to a fine up to $400,000 and an order of restitution.

But Robert J. Becerra, an attorney who represented Sally Qing Miller, who is a Chinese national, and Chemnutra, said the company, the Millers and the government agreed that probation and a fine were an appropriate sentence.

"The Millers and ChemNutra look forward to putting both this case and this tragic matter behind them and hope that today's enhanced awareness of food safety issues will prevent this from ever happening again," Becerra said.

Lance Sandage, defense attorney for Stephen Miller, the owner and chief executive officer of Chemnutra, did not immediately return phone calls Tuesday seeking comment.

Xuzhou Anying Biologic Technology Development Co. and Suzhou Textiles, Silk, Light Industrial Products Arts and Crafts I/E Co. were indicted with 13 felony counts of introduction of adulterated food into interstate commerce and 13 felony counts of introduction of misbranded food into interstate commerce.

The indictment also names Mao Linzhun, Xuzhou's owner, and Zhen Hao Chen, Suzhou's president.

The indictment also alleged that Suzhou Textiles, an export broker, mislabeled 800 metric tons of tainted wheat gluten manufactured by Xuzhou to avoid inspection in China. Suzhou then did not properly declare the contaminated product it shipped to the U.S., the indictment said.

It also said the shipment was falsely declared to the Chinese government in a way that would avoid a mandatory inspection of the company's plants.

According to the indictment, ChemNutra picked up the melamine-tainted product at a port of entry in Kansas City, then sold it to makers of various brands of pet foods. The indictment alleges that Xuzhou added the melamine to artificially boost the protein content of the gluten to meet the requirements specified in Suzhou's contract with ChemNutra.

Prosecutors said adding the melamine, which would allow it to pass chemical inspections for protein content, was cheaper than adding protein to the gluten.

Chinese authorities shut down Xuzhou Anying and revoked its license in 2007.