AVMA 2018: Multistate Listeria Outbreak Due to Raw Milk

Megin Nichols, DVM, MPH, DACVPM, enteric zoonoses activity lead at the CDC, presented at the 2018 American Veterinary Medical Association Convention on a recent listeria outbreak. Here are her key takeaways from that session.

"At the AVMA conference, one of the topics I'll be speaking on is a multistate outbreak of listeria monocytogenes that was associated with drinking raw milk. Now, many of us recognize that consumption of raw milk—meaning milk that has not been pasteurized from a cow or other animal—can carry germs that can make people sick. What we hadn't seen before at the CDC is a multistate outbreak of listeria which can cause really severe illness, especially in people who have weakened immune systems, and when those people consume raw milk they might develop listeria. So, what we hadn't seen is a multistate outbreak where raw milk might have been produced by a cow on Wednesday, shipped across state lines—which is not permissible or legal to do—and then consumed by people who have weakened immune systems.

We had one instance in an outbreak where this occurred, and it actually caused the death of an elderly person and a severe illness which resulted in the hospitalization of another person. So, our lesson learned from this outbreak was No. 1 the importance of really talking to the public about the risks of consuming raw milk and ensuring that they're aware that pasteurized milk really reduces the chance of them getting sick from the germs. And increasing agricultural awareness about the risk of not only producing the raw milk in potentially unsanitary conditions but delivering that raw milk in violation of law across state lines because it can cause a multistate outbreak across the United States. That involves a very intense response with huge economic costs in addition to the tragedy that occurred with the death of the person.

One of the things that we've actually seen in terms of raw milk sales is many states, especially in the past 10 to 15 years, have actually implemented legislation that makes raw milk sales more permissible in their states. What we see is people who drive across state lines to actually purchase raw milk in the states where it's legal, and then they take it back home. We've also seen an increase in internet sales and buyers' clubs. So, internet sales: If you can picture many of the sites that are readily available for use to sell other commonly produced or used home goods, they're actually being used as a conveyance to sell raw milk to consumers. And then buyers' clubs: These are clubs that are popping up all over the internet where producers might have raw milk or other products, such as raw dairy products or even meat sometimes, and advertise them for sale and then a group might get together and organize a system by which those products are transported across state lines. In the case of the outbreak that I mentioned, the raw milk product was transported all the way from a farm in Pennsylvania to consumers in Florida and to consumers in California, which subsequently resulted in illness."