The US Centers for Disease Control and Prevention (CDC) is collaborating with state public health officials to investigate an outbreak of Listeria monocytogenes infections that has been linked to unpasteurised milk produced by Miller’s Organic Farm in Bird-in-Hand, Pennsylvania.
The outbreak affected two people – one in California and one in Florida – in 2014, but was only recently identified by comparing genetic analysis data from bacterial isolates. Both of the people infected required hospital treatment and one subsequently died from listeriosis.
The two cases were linked to unpasteurised milk from Miller’s Organic Farm following FDA testing of samples of raw chocolate milk produced by the company and collected at a raw milk conference in California. The samples tested positive for Listeria and whole genome sequencing (WGS) of the bacteria revealed a close genetic relationship with isolates from the two 2014 cases. It was then established that both of the people involved in the outbreak had consumed raw milk before becoming ill and one had purchased milk from Miller’s Organic Farm.
CDC is recommending that people, especially vulnerable groups such as young children and the elderly, do not consume unpasteurised dairy products because of the potential risk from pathogenic bacteria. There are concerns that raw milk and dairy products produced and distributed by Miller’s Organic Farm may be contaminated and could still be on the market. The investigation is on-going and is using the PulseNet DNA fingerprinting network to look for other cases related to the outbreak.
More information about the investigation can be found here.