The Associated Press reports that the U.S. Department of Agriculture is threatening to shut down three California poultry processing facilities linked to a salmonella outbreak that has sickened 278 people across the country.

The USDA said that Foster Farms, owner of the three facilities, has until Thursday to tell the department how it will fix the problem. The company was notified Monday.

In a letter to the company, the USDA warned that sanitary conditions at the facility “could pose a serious ongoing threat to public health.”

The USDA had posted a consumer alert about the outbreak last week. The illnesses, predominantly in California, have been caused by salmonella Heidelberg and have caused twice the normal rate of hospitalization among victims.

As USA Today reported, the outbreak involves multiple antibiotic-resistant strains and 42 percent of those sickened have been hospitalized, the Centers for Disease Control and Prevention (CDC) said Tuesday.

“That’s a high percentage,” CDC spokeswoman Barbara Reynolds told the newspaper. “You would expect about 20 percent hospitalizations with salmonella Heidelberg.”

The CDC has been hampered in tracing this outbreak because the government shutdown meant the agency had to shut down PulseNet, a national network of public health laboratories that helps spot food-borne-illness outbreaks. It’s one of the CDC’s most important tools in detecting this kind of problem, USA Today said.

“We were trying to do this without the automatic system, and it was nearly impossible,” Reynolds said. Seven of the eight staffers who run the system were furloughed. “We were doing it by hand, and it just become untenable.”

The chicken products were distributed mostly to retail outlets in California, Oregon and Washington state, the FSIS said.

Consumers should look for one of three establishment numbers inside a USDA mark of inspection on the package: P6137, P6137A, P7632.

This is the second time this year Foster Farms has been linked to a national outbreak of salmonella. The company’s raw chicken sickened 134 people in 13 states, including 33 who were hospitalized, before an earlier outbreak ended in July, according to the CDC.

Salmonella typically causes diarrhea, nausea, abdominal cramps, fever and vomiting within eight to 72 hours of eating contaminated food. These symptoms can last up to a week and are particularly dangerous for those with weakened immune systems, babies and the elderly.

Thoroughly washing your hands, utensils and preparation area after handling raw chicken can reduce your risk of spreading the bacteria, and proper cooking — to an internal temperature of 165 degrees Fahrenheit — can also kill the pathogens.