A Column Offered by WCMA Executive Director John Umhoefer
The June issue of the Journal Emerging Infectious Disease made news with a report comingling data on disease outbreaks caused by beverage raw milk and raw milk cheese. Was that pairing fair?
The report by researchers at EpiX Analytics strongly implicates unpasteurized dairy products versus pasteurized beverage milk and cheese. “In conclusion,” the report notes, “outbreaks linked to the consumption of cow’s milk and cheese were estimated to cause on average 761 illnesses and 22 hospitalizations per year in the United States. Unpasteurized products are consumed by a small percentage of the US dairy consumers but cause 95% of illnesses.”
A consumer reading this summary is forced to lump raw milk cheese and beverage raw milk into a single “dangerous” category.
The study goes on to state: “Unpasteurized milk, consumed by only 3.2% of the population, and cheese, consumed by only 1.6% of the population, caused 96% of illnesses caused by contaminated dairy products.” Put another (damning) way, the researchers note that unpasteurized dairy products cause 840 times more illnesses and 45 times more hospitalizations than pasteurized dairy products.
Wisconsin Cheese Makers Association is clearly on record against the sale and consumption of raw (unpasteurized) milk as a beverage. Raw milk simply has no food safety steps or hurdles to stop natural pathogenic organisms from moving through the milking process, into the bottle and to the consumer.
And while the U.S. Food & Drug Administration (FDA) firmly joins WCMA in opposition to beverage raw milk, both our Association and government food safety leaders know raw milk cheeses can be produced safety.
The report in this month’s Emerging Infectious Disease doesn’t separate data on beverage raw milk outbreaks and raw milk cheese outbreaks. But luckily, other government studies from the Center for Disease Control and Prevention (CDC) have.
The CDC reported in a 2012 study that cheese made from raw milk was involved in 27 outbreaks of foodborne illness from 1993 to 2006. Among 121 dairy outbreaks, “65 involved cheese and 56 involved fluid milk. Of the 65 outbreaks involving cheese, 27 (42%) involved cheese made from non-pasteurized milk. Of the 56 outbreaks involving fluid milk, an even higher percentage (82%) involved non-pasteurized milk,” according to a paper in Emerging Infectious Diseases, Vol. 18, No. 3.
A later CDC study tacked six more years of data on beverage raw milk outbreaks. “During 2007–2012, a total of 81 outbreaks associated with non-pasteurized milk were reported from 26 states. These outbreaks resulted in 979 illnesses and 73 hospitalizations,” researchers wrote in Emerging Infectious Diseases, Vol. 21, No. 1.
Adding the two reports’ totals of beverage raw milk outbreaks yields 127 raw milk incidents, the amount reported prominently on Foodsafety.gov, a U.S. Department of Health & Human Services website: “From 1993 through 2012, 127 outbreaks reported to CDC were linked to raw milk. These outbreaks sickened 1,909 people, and caused 144 people to be hospitalized. Most of the 127 outbreaks were caused by Campylobacter, Shiga toxin-producing Escherichia coli, or Salmonella.”
Raw milk cheese has been responsible for illness outbreaks, but beverage raw milk incidents are far more common.
In 1990, researchers at the University of Wisconsin pointed out the hurdles that cheesemaking presents to pathogens – even for cheese made from unpasteurized milk.
“A multiplicity of practices other than pasteurization or heat-treatment contribute significantly to the microbiological safety of cheese. Some, such as milk quality management, lactic culture management, pH control, salt addition, and controlled curing conditions are established technologies. Others represent potential opportunities, such as natural inhibitory substances in milk, and antibacterial substances, e.g. nisin and lysozyme,” researchers wrote in the Journal of Food Protection, Vol. 53, No. 5.
Raw beverage milk, on the other hand, lacks these hurdles. A USDA study of pathogens in bulk tank milk published in the Journal of Dairy Science (Vol. 87, Issue 9) found 2.6 percent of 861 bulk tanks in 21 states carried Salmonella. In addition, Listeria monocytogenes was found in 6.5% of samples.
Last summer, FDA reported on a sweeping program to collect and test foreign and domestic cheeses made from unpasteurized milk. Rather than looking at illnesses, this study directly tested cheese for pathogens. The agency collected 1,606 samples of raw milk cheese – 473 samples were domestically produced and 1,133 samples were international raw milk cheeses.
Common pathogens Salmonella and E. Coli 0157 were absent in all of the domestic samples, and just 0.26% of international cheeses held Salmonella. Listeria monocytogenes was found in five international cheeses and four semi-soft U.S. cheeses and one hard cheese – only 1 percent of the domestic cheese samples.
Listeria, FDA concluded in its “Summary Report: Raw Milk Cheese Aged 60 Days,” remains a concern in semi-soft cheese and “the agency will be actively working with industry to address strategies to significantly minimize or prevent contamination.”
All raw-milk dairy products must be made with utmost care, and dairy processors large and small must readily adopt safety advances that protect consumers against pathogens. But the processing, handling, and contamination-potential of raw milk cheese and beverage raw milk are not the same, and should not conjoined in a study of dairy food safety.