Collaborative investigative efforts of state, local, and federal public health and regulatory officials indicate that raw milk produced by Miller's Organic Farm in Bird-In-Hand, Pennsylvania, is the likely source of this outbreak.
Two people infected with the outbreak strain of Listeria were reported from California (1) and Florida (1). Both illnesses occurred in 2014.
Both people were hospitalized, and the ill person in Florida died as a result of listeriosis.
Although the two illnesses occurred in 2014, the source of these illnesses wasn't known until January 29, 2016, when the U.S. Food and Drug Administration informed CDC that whole genome sequencing of Listeria bacteria from raw chocolate milk produced by Miller's Organic Farm showed that it was closely related genetically to Listeria bacteria from the two ill people described above.
Because Listeria was recently found in raw milk produced by Miller's Organic Farm, CDC is concerned that conditions may exist at the farm that may cause further contamination of raw milk and raw dairy products distributed by this company and make people sick.
Raw milk is milk from cows or other animals that has not been pasteurized to kill harmful bacteria. This raw, unpasteurized milk can carry dangerous bacteria such as Listeria, Salmonella, E. coli, and Campylobacter, which are responsible for causing numerous foodborne illnesses and outbreaks.
The CDC recommends that people drink and eat only pasteurized dairy products (including soft cheese, ice cream, and yogurt).
Pasteurization is the process of heating milk to a high enough temperature for a long enough time to kill dangerous bacteria.
This is especially important for people at higher risk for foodborne illness: children younger than 5, pregnant women, adults 65 and older, and people with weakened immune systems.