Seven people have been sickened with the outbreak strain from four states, said the US Centers for Disease Control and Prevention (CDC).
The outbreak strain was defined by pulsed-field gel electrophoresis (PFGE), added the agency.
Beef produced by Adams Farm Slaughterhouse in Athol, Massachusetts has been named as the likely source.
Adams Farm: USDA’s cross contamination fear 'unjustified and unrealistic’
The firm said it had narrowed down the point of contamination to two days in August and was working with farmer customers to ensure that none of it is sold and for them to inform customers.
“It is the usual practice for all product that is cut and packaged on the same days that any contaminated product is packaged to be part of a recall and we took immediate steps to ensure that all product associated with those two days of production have been recalled.”
However, it added the scale of the recall requested by USDA was ‘unjustified and unrealistic’.
“The USDA has instructed us to also recall product from all animals slaughtered over a seven week period, many weeks before and after the actual contamination took place, because of their fear, which is both unjustified and unrealistic, that there may have been cross contamination on the day of slaughter despite each carcass being hung separately from the time of kill to being cut and packaged.
“While we are very concerned over the USDA’s over-reaction and its impact on our customers, we have fully cooperated with their requirements but want our customers to be aware that we stand behind all of our products and will continue to stand behind all of our farmer customers and their consumers.”
Five people interviewed reported eating ground beef supplied by the company in the week before they became ill.
Health agency testing finds outbreak strain
The Connecticut Department of Public Health collected leftover ground beef from an ill person's home and from a restaurant for testing; produced by Adams Farm Slaughterhouse.
Test results showed the outbreak strain in both samples of the leftover ground beef.
Adams Farm Slaughterhouse recalled various cuts of beef, veal and bison products from animals slaughtered on July 15, 25 and 27 and August 3, 8, 10, 11, 17, 24 and 26 and further processed and packed between July 21 and September 22.
Items were sent to farmer's markets, retail locations, and restaurants in Massachusetts, Connecticut, and eastern New York and may have been shipped to neighbouring states.
The US Department of Agriculture’s Food Safety and Inspection Service (USDA-FSIS) listed the lot numbers and products subject to the recall.
FSIS advised consumers to only consume beef and ground meat cooked to 145° F for beef (with a three minute rest time) and 160° F for ground meat.
Five people have been hospitalized but none have developed hemolytic uremic syndrome (HUS), a type of kidney failure, and no deaths have been reported.
Illness dates range from June 27 to September 4 and ill people range in age from one to 74 with 57% female.
Illnesses after September 8 might not yet be reported as it takes an average of two to three weeks between a person becoming ill and when illness is reported.
Hepatitis A outbreak update
Meanwhile, an outbreak of foodborne hepatitis A from frozen strawberries imported from Egypt has grown to 119 cases in eight states with 47 people hospitalized.
Nearly all ill people interviewed drank smoothies containing strawberries at Tropical Smoothie Café locations prior to August 8 in Maryland, North Carolina, Virginia and West Virginia.
Tropical Smoothie Café removed the contaminated product as of August 8 but symptoms of hepatitis A virus infection can take up to 50 days to appear.
It has since switched to another supplier for all restaurants nationwide, sourcing strawberries from the Americas.
The firm said it has launched a review of sourcing and safety practices, including retaining the services of an epidemiologist and expert in food supply chain and safety.
It has also strengthened food safety training and certification processes for employees, as well as protocols and policies for cleaning, sanitizing and reporting.
The Food and Drug Administration has increased surveillance of imported strawberries and has contacted the Egyptian International Health Regulations National Focal Point during the investigation.