The Colorado Department of Agriculture (CDA) analyzed samples of the fast food chain’s beef patties and found no evidence of the bacteria.
The CDA has no plans for additional testing, the business added.
In reaction to the epidemic, McDonald’s halted Quarter Pounder sales in about a sixth of its US locations last week.
“The problem seems to be limited to a specific ingredient and geographic area, and we are still extremely certain that any tainted product associated with this outbreak.
McDonald’s Chief Supply Chain Officer for North America, Cesar Piña, said in a statement.
The slivered onions in Quarter Pounders were previously identified by the US Food and Drug Administration as an additional possible cause of the incident.
McDonald’s announced that it had cut the onions out of its supply chain and ceased doing business with the supplier.
According to McDonald’s, the 900 eateries that previously purchased slivered onions from Taylor Farms’ Colorado Springs operation will start selling Quarter Pounders without them.
