Raw Milk Illness Rate Is Low Per Serving Consumed and Per Consumer
Raw milk illness is measured two ways in the epidemiological literature: per serving consumed and per consumer. The per-serving measure produces the widely quoted 840x ratio. The per-consumer measure describes how often people who drink raw milk actually get sick. Both come from the same underlying outbreak data, and both show low absolute rates.
Per serving consumed
The per-serving comparison comes from Costard et al. 2017, published in Emerging Infectious Diseases. The study modeled outbreak-related illness from cow’s milk and cheese in the United States using outbreak data from 2009 to 2014 for four pathogens: Salmonella, Campylobacter, Shiga toxin-producing E. coli and Listeria monocytogenes.
The illness rate per billion servings was 840 times higher for unpasteurized dairy than for pasteurized dairy (95% credible interval 611 to 1,158). For hospitalizations the ratio was 45.
A per-serving ratio is a standard tool for comparing two versions of the same product. It produces a large number here because the pasteurized rate it is divided by is very low, and because pasteurized milk is consumed in enormous volume. The ratio does not say how many people get sick. The study’s absolute estimates do: about 761 outbreak-related illnesses and 22 hospitalizations a year from all dairy combined, with 96% of those illnesses, about 730 a year, from unpasteurized milk and cheese. Those figures are modeled estimates adjusted for underreporting and underdiagnosis; confirmed outbreak cases from raw dairy in the same period averaged about 108 a year.
A full explanation of the ratio is in What “840 Times More Likely to Get Sick from Raw Milk” Actually Measures.
The per-consumer rate and the studies behind it are summarized in raw milk statistics.
Per consumer
Dividing annual illnesses by the number of people who drink raw milk gives the per-consumer rate. Two published consumer estimates are available, from two different surveys.
| Consumer estimate | Source | Approximate consumers | Illness rate (730 per year) |
|---|---|---|---|
| 3.2% of the US population | FoodNet Population Survey, 2006 to 2007, as used by Costard et al. | about 9.6 million | 0.0076%, about 1 in 13,000 |
| 4.4% of US adults | FDA surveys, 2016 and 2019 (Lando et al. 2022) | about 11 million | 0.0066%, about 1 in 15,000 |
The two denominators come from different surveys, years and populations (the FDA surveys counted adults only), so the honest range is about 1 in 13,000 to 1 in 15,000 per year. Hospitalization, using Costard’s estimate of about 21 hospitalizations a year attributable to unpasteurized dairy, works out to roughly 1 in 450,000 to 1 in 520,000.
Both calculations are conservative in one respect: the 730 illnesses include raw cheese, while the denominators count only raw milk drinkers.
Consumption frequency
The per-consumer figure treats everyone who drank raw milk at least once in a year as equivalent. Lando et al. 2022, drawing on FDA’s 2016 Food Safety Survey and 2019 Food Safety and Nutrition Survey, also reported how often people drink it:
| Frequency | Share of US adults | Approximate adults |
|---|---|---|
| At least once in the past year | 4.4% | about 11 million |
| Once a month or more | 1.6% | about 4 million |
| Once a week or more | 1.0% | about 2.5 million |
Applying all 730 annual illnesses only to frequent drinkers produces a ceiling, not an estimate, because it assumes no infrequent drinker ever gets sick:
| Consumer group | Approximate consumers | Illness rate if all 730 illnesses fell in this group |
|---|---|---|
| All past-year consumers | about 11 million | 0.0066%, about 1 in 15,000 |
| Once a month or more | about 4 million | 0.018%, about 1 in 5,500 |
| Once a week or more | about 2.5 million | 0.029%, about 1 in 3,400 |
Even at the ceiling, with every illness assigned to weekly drinkers, the rate is under three in ten thousand per year.
Limitations of outbreak-based rates
The illness count in both measures is limited to outbreak-related cases. Illness that occurs outside a recognized outbreak (sporadic illness) is not included, and for most foods, sporadic illness is the larger share. A 2014 Minnesota study (Robinson et al.) found that lab-confirmed sporadic patients who reported drinking raw milk outnumbered outbreak cases by about 25 to 1, although the authors noted those sporadic illnesses “could not be definitively linked” to the milk. How that affects comparisons with other foods is covered in Comparing Raw Milk Foodborne Illness Data with Other Foods.
The consumer estimates are also dated. No national raw milk consumption survey has been published with data after 2019, and sales data since then point to a larger consumer base, discussed in Raw Milk Illness Rate Per Consumer: Updated Data from 2022.
