Salmonella in chicken from the Foster Farms poultry processing plant in California continues to make people sick a year after the first cases were identified.
Fifty new cases were identified within the last three months, bringing to 574 the total number of people infected with strains tied to the outbreak that began more than a year ago, the federal Centers for Disease Control and Prevention said.
More than a third of those people felled since March 1 had to be hospitalized for treatment against Salmonella Heidelberg strain of food-poisoning bacteria.
Thirteen percent of patients developed blood infections as a result of their illness, the Centers for Disease Control says. None of the sickened people have died.
The investigation led to the recall in October 2013 of 23,000 cooked rotisserie chicken products sold at a Costco store in San Francisco.
There have been cases linked to this chicken in 27 states and Puerto Rico, but 77 per cent of the victims are Californians.