The shutdown of the US federal government is putting the country's citizens "at risk", consumer watchdog The Center for Science in the Public Interest has claimed in the wake of the salmonella outbreak that has affected 18 states.

Almost 300 people have fallen ill from strains of salmonella heidelberg linked to raw poultry products made at three plants owned by US poultry group Foster Farms.

The USDA's Food Safety and Inspection Service said on Monday (7 October) there had been an estimated 278 illnesses "recently reported" in 18 states. Those who had fallen ill were "predominantly" in California - where the three Foster Farms facilities are located - the FSIS said.

In a statement issued yesterday, the CSPI said seven strains of salmonella were responsible for the illnesses and warned some may be "highly resistant" to treatment by antibiotics.

The watchdog said the outbreak comes with "key food safety personnel" at the U.S. Department of Agriculture and key disease-surveillance scientists at the Centers for Disease Control and Prevention not at work due to the federal government shutdown.

"The number of people we know to be ill is just the tip of the iceberg," said CSPI food safety director Caroline Smith DeWaal. "This outbreak shows that is a terrible time for government public health officials to be locked out of their offices and labs, and for government websites to go dark. The salmonella strains are showing resistance to multiple antibiotics, and that means more people are going to the hospital and their infections will be harder for physicians to treat.

"The Department of Agriculture should direct Foster Farms to recall all of the potentially contaminated chicken from the market. Antibiotic-resistant Salmonella is too hot to handle in consumers' kitchens. This outbreak is further evidence that consumers need our government back at work, with food-safety agencies adequately funded."