SACRAMENTO, California (Reuters) - A California slaughterhouse ordered shut down for a week by federal regulators over a graphic video showing mistreatment of cows there said on Friday it had resumed full operations after passing a government food safety inspection.

The U.S. Department of Agriculture (USDA) allowed the Central Valley Meat Company to reopen its plant on Monday after operators of the facility agreed to improve their handling of animals in the slaughtering process.

But the USDA said at the time that an investigation into possible food safety violations was continuing.

On Friday, Central Valley Meat issued a statement saying the USDA had completed its inspection and informed the company "there are no food safety issues whatsoever with our product or operations".

"As a result, we are resuming full operations and production immediately," the statement added.

The government suspended operations at the plant on August 19 after animal rights activists gave the USDA a video showing cows at the facility flailing wildly as they were dragged by one leg on a conveyor belt on their way to slaughter.

The video, published online by the activist group Compassion Over Killing, also showed lame, sick former dairy cows being shot in the head multiple times and struggling before they died. In one part of the video, taken by an undercover activist, a worker was seen standing on a cow's nostrils to kill the animal after it was shot.

Central Valley Meat said it had worked with federal inspectors and industry experts to "develop and implement a USDA-approved action plan that will provide better training for our workers and better monitoring of our facilities".

The family-run plant, located in California's agricultural heartland, employs 450 people.

(Reporting by Steve Gorman and Mary Slosson; Editing by Pravin Char)