A previous report on 16 January stated that the outbreak appeared to be over, but since then a further 51 cases in five US states have been reported. A total of 481 people have now been affected by the outbreak since 1 March 2013 and 38% of those have required hospital treatment.
Seven different outbreak strains of Salmonella Heidelberg have been isolated from those affected and from Foster Farms brand chicken. The new cases were discovered when surveillance showed that infections by two of the rare outbreak strains were significantly higher than would be expected if the outbreak were over.
CDC and the USDA Food Safety and Inspection Service (FSIS) have reiterated their advice to consumers to handle and cook raw chicken carefully to avoid infection. No product recall has been initiated since occasional Salmonella contamination in raw poultry is not considered unusual.
More information about the investigation can be found here.