ATLANTA – The Centers for Disease Control and the US Department of Agriculture's Food Safety and Inspection Service issued a final update report on their investigation of a multi-state outbreak of Salmonella Typhimurium infections that were linked to ground beef sold from Hannaford Supermarkets.

The investigations, which started in mid-December, revealed that 20 people in seven states were infected with the foodborne pathogen and seven people were hospitalized, according to CDC. The victims ranged in age from 1 year to 79 years old. They reside in Hawaii, Kentucky, Massachusetts, Maine, New Hampshire, New York and Vermont.

The CDC said the strain of Salmonella Typhimurium is resistant to several commonly prescribed antibiotics, including amoxicillin, ampicillin and streptomycin. Investigators used DNA "fingerprint" technology to identify cases that may have been associated with the outbreak. The State of Maine Health and Environment Testing Laboratory and the New York State Department of Health isolated the outbreak strain from two separate samples of leftover ground beef purchased from Hannaford stores.

Hannaford, which is based in Scarborough, Maine, cooperated fully with investigators, and initiated a recall of an undetermined amount of fresh ground beef products on Dec. 15, 2011. The various ground beef packages bear sell-by dates of Dec. 17, 2011, or earlier and were sold at Hannaford stores throughout Maine, Massachusetts, New Hampshire, New York and Vermont, according to FSIS.