>>> there is a story in the news linking this shutdown with a serious salmonella outbreak traced to chicken. close to 300 people are known to have been sickened already in this. the vast majority of them in california . investigators believe the outbreak is larger than that. but the agency responsible for monitoring and stopping widespread illness, the cdc, is largely shut down. we get our report tonight from nbc's tom costello.

>> reporter: in chula vista , california , the blair family is convinced they are recovering from food poisoning . they bought foster farms chicken and ate it that night.

>> i felt violently ill. i had to run to the bathroom every few minutes. i thought it was the stomach flu.

>> reporter: their chicken has the same lot numbers as those with salmonella outbreak. so far 278 people were sickened. for every reported case 25 more go up reported. this outbreak combined with another outbreak involving foster farms last year could have sickened nearly 10,000 people. investigators believe the salmonella this time came from three foster farms processing plants in california . today, the usda threatened to shut the plants down.

>> we have concerns that they have difficulties in producing a safe product now.

>> reporter: particularly alarming, some of the salmonella strains are resistant to antibiotics. the hospitalization rate double what's normal. the outbreak comes as the centers for disease control is hobbled by the government shutdown . 9,000 of the 13,000 workers furloughed. they have called back 30 staffers to help t with the salmonella outbreak.

>> it's outrageous that congress is keeping our top experts at home when the public e health demands that these people be at work.

>> reporter: in a statement, foster farms says it deeply re grets any foodborne illness that may be associated with any of our products. experts say it is important to clean chicken thoroughly, keep it away from counter tops and salmonella can usually be killed when cooking chicken to an internal temperature of 165 degrees. so far foster farms said it's not recalling product bus it is implementing additional safety measures in processing. tom costello, nbc news, washington.