However, despite the use-by-date having passed, the agency urged consumers to check their freezers for the recalled products.
The outbreak of Salmonella Typhimurium from ground beef saw cases reported from six states, Arizona (1), Illinois (2), Iowa (1), Michigan (9), Wisconsin (8) and Pennsylvania (1).
The PFGE pattern has rarely been seen before in PulseNet and in the past typically caused 0-1 cases per month, said the agency.
PulseNet is the national subtyping network made up of state and local public health laboratories and federal food regulatory laboratories that performs molecular surveillance of foodborne infections.
Link to ground beef
Ground beef produced by Jouni Meats and Gab Halal Foods were found to be the likely sources of the infections.
Illness onset dates ranged from 9 December 2012 to 20 February 2013, according to available information, said the CDC.
Ill persons ranged in age from two to 87 years, with a median age of 45 years.
Fifty-five percent were male and among people with available information, seven out of 14 (50%) were hospitalized.
On January 24, 2013, Jouni Meats recalled 500 pounds of ground beef products and the day after, Gab Halal Foods recalled 550 pounds of ground beef products.
Investigation method
Public health investigators used DNA "fingerprints" of salmonellabacteria obtained through diagnostic testing with pulsed-field gel electrophoresis (PFGE) to identify cases of illness that may be part of the outbreak.
Initial investigations focused on six ill persons in Michigan and one in Arizona who reported eating at the same restaurant before their illness began.
All seven reported eating raw ground beef kibbeh (a dish typically made of finely ground red meat, usually beef, minced onions, and bulghur wheat) at this restaurant before becoming ill.
An additional nine people were interviewed about foods consumed and other exposures during the week before becoming ill.
Although several reported eating beef prior to becoming ill, a likely source was not identified that linked these illnesses with those at the restaurant.