Cheese and Listeria monocytogenes
Recently, a cheese made from unpasteurized milk was recalled following an outbreak of Listeria monocytogenes. Vulto Creamery has issued a complete recall of their raw milk cheeses. Tragically, consumption of the contaminated cheese has resulted in two deaths. Our hearts go out to those who have lost loved ones.
We want to reassure consumers of the overall safety of cheeses produced in the United States and to share some background information on Listeria monocytogenes contamination.
Cheeses made from raw milk have been produced — and enjoyed — for centuries, not only in Europe but also in North America and throughout the world. But today, even the most traditional product is subject to government food safety rules and regulations. Scientific studies support methods used to produce these traditional products safely, and artisan cheese makers take this responsibility very seriously. Cheese makers work closely with the FDA and state safety inspectors in being diligent about product quality, sanitation, labeling, and training. In addition, large and small retailers have HACCP plans in place to guard against cross-contamination.
A fatal outcome, such as we’ve recently witnessed, is exceedingly rare. We are waiting to learn the final results of the investigation into this outbreak. Precisely because listeriosis, although rare, can be lethal, we want to assure the public that cheese makers are continuously strengthening their protocols to prevent contamination.
Pasteurization, we wish to stress, is no magic bullet to prevent contamination from Listeria monocytogenes. In most cases, when a cheese is contaminated with Listeria monocytogenes, this occurs during or after production (regardless of whether the milk used was pasteurized). Listeria monocytogenes is a ubiquitous environmental pathogen. This pathogen can persist in soil for long periods of time, and can infect green plants growing on contaminated soil. Listeria monocytogenes may thrive in wet silage used to feed cows, goats, and sheeps. It’s well known that animals ingesting Listeria-contaminated silage can shed Listeria in their milk. For this reason, artisan cheese makers are advised to feed dry hay or to feed animals on pasture, in the unlikely case there could be contamination.
If it contaminates dairy processing facilities, Listeria monocytogenes can reside and persist in floor drains, on floors or processing equipment, and in brines and brushes. Wood boards used to age some cheeses do not pose a threat, as established by research conducted in France. According to a study published in 2010 in the Journal Food Control, resident biofilms present on wooden shelves used for cheese ripening may actually inhibit the proliferation of Listeria monocytogenes. This study is available on our resources page.
Any possible contamination by Listeria monocytogenes can be detected when risk reduction protocols to test and eliminate niches for this pathogen are followed. These protocols should be in place at all times and periodically reviewed in all food processing plants.
Oldways and the Oldways Cheese Coalition are passionate advocates of raw milk cheese and the producers that make them. Our work concentrates in countering misinformation and sensationalist stories that try to single out and vilify a specific product. We promote scientific knowledge as the basis of a common ground approach when informing the public about the food we consume. We firmly believe that consumers should know more. Educated consumers are empowered to make their own choices with confidence.
We know that people want to enjoy raw milk cheeses. According to a survey conducted by the Oldways Cheese Coalition in 2015, 90% of questioned cheese-lovers in the US believe they should be able to choose raw milk cheeses and understand the difference between cheeses made with pasteurized and unpasteurized milk. This high degree of understanding is only possible due to the efforts of raw milk cheese producers and advocates. We have for decades armed consumers with scientific-based facts about a product people love. Our survey also found that 86% of cheese-lovers purchase raw milk cheeses to support small artisans and the rural economies where they are based. To review more information on our survey, please follow this link.
Collective work around the globe has shown that Listeria monocytogenes is a risk that can be successfully managed by cheese makers as evidenced by the large volume of raw milk cheese that is consumed without incident. In addition to testing their production facilities, many cheesemakers test their cheeses during manufacture to ensure absence of Listeria monocytogenes and other pathogens.
The public should be encouraged to know that the systems in place to detect, contain, and recall contaminated products are working as expected once the contamination had been identified. We stress the importance of following the recommendations of the CDC, FDA, and your local health authority regarding recalled products. Information can be found on their websites.
The Oldways Cheese Coalition calls on Congress to invest further in strengthening our regulatory agencies, while maintaining an open dialogue with scientist and producers. We rely on collaboration between food producers, distributors, retailers, and regulators to maintain our food supply safe.
Recently, our Program Director was quoted in the New York Times article, “Two People Die After Eating Raw Milk Cheese Made in New York State.” The article oversimplifies and paraphrases what was a lengthy and nuanced conversation. We are disappointed by the tenor and misleading message of the story. We will continue our work to inform the public of the history and safety of raw milk cheeses generally.