Timeline of Events

June 17, 2013: PulseNet reports a cluster of illnesses on the West Coast, primarily California, with a single rare PFGE pattern of Salmonella Heidelberg (PFGE Pattern #1) to the Outbreak Response Team at CDC. PulseNet identifies a non-human retail chicken isolate from the National Antimicrobial Resistance Monitoring System (NARMS) retail meat surveillance program with PFGE Pattern #1.

June 28, 2013: USDA-FSIS is notified by CDC of its multistate investigation of PFGE Pattern #1.

July 1, 2013: USDA-FSIS notifies CDC that the NARMS retail chicken isolate with PFGE Pattern #1 was Foster Farms brand chicken. PulseNet identifies a second cluster of illnesses with another rare PFGE pattern of Salmonella Heidelberg (PFGE Pattern #2).

July 3, 2013: CDC hosts the first multistate conference call for the first cluster, PFGE Pattern #1.

July 5, 2013: USDA-FSIS conference call with Foster Farms to provide a summary of the investigation to date.

July 8, 2013: PulseNet identifies a third cluster of illnesses with a common PFGE pattern of Salmonella Heidelberg (PFGE Pattern #3).

July 12, 2013: Washington State identifies a fourth cluster of a very rare PFGE pattern of Salmonella Heidelberg (PFGE Pattern #4). An additional PFGE pattern, PFGE Pattern #5, was also identified based on similar epidemiologic data.

July 18, 2013: Working with California, CDC combines PFGE Patterns #1-5 into a single investigation due to some of the patterns being similar and a high proportion of ill persons reporting that they had consumed Foster Farms brand chicken.

July 22, 2013: USDA-FSIS begins working with California public health officials to obtain shopper histories for product traceback.

July 29, 2013: CDC begins investigating two additional Salmonella Heidelberg PFGE patterns (PFGE Patterns #6 and 7) due to high proportion of ill persons reporting chicken consumption and similar demographics and geographic distribution.

July 30, 2013: Outbreak Response Team receives antimicrobial susceptibility testing results from the CDC NARMS laboratory for 4 human isolates matching PFGE Patterns #1 and #2. Resistance to several commonly used antibiotics was identified.

August 6, 2013: Intact leftover product from ill person’s home in Washington State tests positive for PFGE Pattern #4. Product traces back to Foster Farms.

August 9, 2013: First joint USDA-FSIS/CDC conference call with Foster Farms to inform the firm about the outbreak and the link to Foster Farms brand chicken.

August 21, 2013: USDA-FSIS begins internal meetings on proposed epidemiologically based intensified sampling at four Foster Farms establishments identified during traceback.

September 4, 2013: USDA-FSIS finalizes its intensified sampling plan focusing on post-chilled product undergoing additional handling within the establishment implicated in illnesses.

September 9 – 27, 2013: USDA-FSIS conducts onsite investigation at four establishments. Intensified Salmonella testing conducted during the investigation.

September 24 – 25, 2013: Preliminary intensified Salmonella sampling results shared with CDC.

September 30, 2013: Cluster of Salmonella Heidelberg illnesses identified in South San Francisco linked to rotisserie chicken sold at a single Costco store location. Two samples of leftover rotisserie chicken collected from ill persons for testing.

October 7, 2013: USDA-FSIS issues “Notice of Intended Enforcement” to Foster Farms and releases a “Public Health Alert” urging consumers to handle chicken safely.

October 8, 2013: CDC posts first outbreak investigation web announcement.

October 10, 2013: Outbreak Response Team receives antimicrobial susceptibility testing results from the CDC NARMS laboratory for 5 additional human isolates matching PFGE Patterns #2 and #4. Resistance to several commonly used antibiotics was identified.

October 11, 2013: Laboratory results identified PFGE pattern #1 in both samples of leftover cooked rotisserie chicken sold at the single Costco store location.

October 12 and October 17, 2013: FSIS announces the recall of more than 23,000 units of cooked rotisserie chicken products sold at the single Costco store location due to potential cross-contamination after cooking.