An outbreak of Salmonella Heidelberg has spread to 18 states and has sickened nearly 300, prompting the return of some 30 CDC staffers furloughed during the government shutdown to work on the case.

The U.S. Department of Agriculture (USDA) was the agency that sourced the outbreak to raw chicken products from three Foster Farms facilities in California, although there is no clear indication of which products specifically are affected or the time period in which these products were released, the agency said in a news brief.

The CDC, like many other government agencies, has been operating under "minimal support," and until Tuesday had only two of 80 foodborne pathogen-analyzing staff on duty, according to a report by ABC News.

But on Tuesday, “about 30 people working on foodborne analysis and outbreak response [were brought back to work], including bringing back about 10 people” who specialize in that area, the agency said in an email to MedPage Today.

These returned staffers will “find additional cases nationwide, characterize the outbreak, and characterize the bacteria for antibiotic resistance,” the agency’s email continued.

Although the USDA isn't operating at full capacity either, according to a statement on the agency's Food Safety and Inspection Service (FSIS) website, "meat, poultry and processed egg inspection activities, as well as those services necessary to support inspection activities, will be maintained" during the government shutdown.

Affected products were "mainly distributed to retail outlets in California, Oregon, and Washington State," the USDA said in the statement, although the outbreak has expanded well beyond those states' borders, affecting an estimated 278 patients.

Although no specific products have been identified, the USDA noted that raw products from Foster Farms are labeled with P6137, P6137A, or P7632 on the USDA mark of inspection on the packaging.

The pathogen was linked back to Foster Farms' products through epidemiologic, laboratory, and traceback investigations that were carried out by local, state, and federal officials.

Foster Farms is not recalling their raw chicken products, the company said in its own press release. They noted that their chicken products are safe to consume if properly handled and fully cooked, citing the FSIS' instructions to cook raw or frozen poultry to a minimum internal temperature of 165º F.

The company also noted that they are working together with the FSIS and CDC in the ongoing investigation.

The USDA also warned consumers that Salmonella infection can be potentially fatal, particularly in patients with compromised immune systems, infants, and older patients, and that symptoms can include diarrhea, abdominal cramps, and fever within 8 to 72 hours of consuming contaminated products.

UPDATE: This article, originally published Oct. 8, 2013, at 3:09 p.m, was updated with new material Oct. 8, 2013, at 6:30 p.m.