According to state and federal public health officials, Roos Foods' cheese products sold in Maryland, Virgiia and the District of Columbia were the source of the Listeria outbreak. On February 15, 2014, the pathogen Listeria monocytogenes was isolated from a sample of Cuajada en Terron (Fresh Cheese Curd) manufactured by Roos Foods and sold at Mega Mart, a retail store in Manassas, Virginia.
The strain of Listeria monocytogenes identified was the same strain of the bacteria that has caused 8 cases of listeriosis in two states. The CDC reports that a total of 8 persons infected with the outbreak strain of Listeria monocytogenes have been reported from two states. The number of ill people identified in each state is as follows: California (1), Maryland (7).