Raw Milk Legalization and Foodborne Illness: Outbreak Rates Fell as Access Expanded
A persistent claim in public health literature holds that legalizing raw milk sales leads to more foodborne illness outbreaks. The claim has a real research foundation, but the studies behind it carry methodological limitations that more recent data have exposed. A closer look at the evidence clarifies why the original conclusion has not held up over time.
Where the Claim Originates
The primary source is Langer et al. (2012), published in Emerging Infectious Diseases, the peer-reviewed journal of the Centers for Disease Control and Prevention (CDC). The study reviewed dairy-related disease outbreaks across all 50 states from 1993 to 2006 and found that states where raw milk sale was legal had more than twice the outbreak rate of states where it was prohibited. It also calculated that raw milk outbreaks occurred at a rate roughly 150 times higher than pasteurized milk outbreaks, adjusted for each product’s estimated share of total consumption.
A follow-up by Mungai et al. (2015), also published in Emerging Infectious Diseases, extended the analysis through 2012 and found that outbreaks linked to nonpasteurized milk had increased. The authors projected that further legalization would probably lead to more outbreaks and illnesses.
These two papers are the foundation of the claim as it circulates in public health communications and media coverage. Both are legitimate peer-reviewed studies.
| Study | Period | Method | Finding |
|---|---|---|---|
| Langer et al. (2012) | 1993–2006 | Raw outbreak counts by state legal status | Legal states had more than 2x the outbreak rate of illegal states |
| Mungai et al. (2015) | 2007–2012 | Raw outbreak counts by state legal status | Outbreaks increased; further legalization projected to worsen this |
| Whitehead & Lake (2018) | 2005–2016 | Consumption-adjusted outbreak rate | Rate declined 74%; strong negative correlation with legal access (r = -0.83) |
| Stephenson et al. (2024) | 2005–2020 | Before/after state law changes, 7 states | No association between increased legalization and increased illness |
The Core Methodological Problem
Both studies compared raw outbreak counts between legal and illegal states without adequately controlling for consumption volume. Legal states have substantially higher raw milk consumption. More people drinking raw milk produces more potential illness cases by definition, regardless of per-serving risk.
The relevant scientific question is not whether total case counts differ between legal and illegal states. It is whether the risk per serving changes when access expands. Neither the Langer nor the Mungai study addressed that question directly.
What Consumption-Adjusted Data Shows
Whitehead and Lake (2018), published in PLOS Currents: Outbreaks, reanalyzed CDC data from 2005 to 2016 with consumption volume factored in using state licensing records as a proxy. The results showed that the outbreak rate associated with unpasteurized milk had been declining since 2010 despite increasing legal distribution. Controlling for both population growth and consumption growth, the outbreak rate had decreased by 74% since 2005.
The underlying annual outbreak counts, drawn directly from the CDC NORS dataset, are as follows. Note that 2009 is excluded per the paper due to documented data quality issues in NORS that year.
| Year | Outbreaks (NORS) | States with legal access |
|---|---|---|
| 2005 | 10 | 28 |
| 2006 | 10 | 28 |
| 2007 | 9 | 29 |
| 2008 | 12 | 30 |
| 2009 | — (excluded) | 30 |
| 2010 | 18 | 30 |
| 2011 | 18 | 31 |
| 2012 | 14 | 30 |
| 2013 | 16 | 32 |
| 2014 | 16 | 34 |
| 2015 | 11 | 37 |
| 2016 | 13 | 40 |
Outbreak counts reflect Whitehead and Lake’s corrected NORS figures for unpasteurized fluid milk, food transmission mode, IFSAC dairy category. Legal-access state counts are from Figure 1 of the same paper.
The direction of the correlation ran opposite to what the earlier studies implied. The Pearson correlation between the number of states with legal access and the consumption-scaled outbreak rate was -0.83, indicating a strong negative relationship when consumption was properly accounted for.
The 2024 Stephenson Study
The most recent analysis extended this inquiry further. Stephenson, Coleman, and Azzolina (2024), published in the Journal of Epidemiology and Global Health, examined CDC outbreak data for the full 2005 to 2020 period across all transmission sources. Their analysis found no trend of increasing raw milk illnesses associated with increased legalization, based on statistical comparisons across seven states with data available both before and after their laws changed.
The same researchers examined which foods were responsible for the most severe outcomes over the study period. According to a summary published by the Raw Milk Institute, fatal foodborne illnesses were dominated by fruits, vegetables, peanut butter, and pasteurized dairy products.
The Role of On-Farm Safety Programs
The Whitehead and Lake study identified a plausible mechanism for the declining outbreak rate: the expansion of on-farm food safety training programs modeled on the HACCP (hazard analysis and critical control points) framework developed for meat processing.
Pennsylvania provides a concrete illustration. Outbreaks occurred annually from 2006 to 2014, then stopped for two consecutive years before one isolated outbreak in 2017. The pause coincided with a major Pennsylvania raw milk farm completing RAWMI safety training in 2014. That farm had previously accounted for 57% of all unpasteurized milk-related illnesses reported nationwide in 2012. No outbreaks have been linked to its products since. The full case detail is documented in the Whitehead and Lake study.
This pattern parallels what occurred in meat processing. The introduction of HACCP systems in U.S. meat processing plants in 1997 produced a 42% decline in E. coli-related illnesses over the subsequent seven years. The analogy suggests that production standards, rather than legal status, are the more relevant variable in determining illness rates.
Absolute Burden in Context
The 96% figure frequently cited in coverage of raw milk refers to a 2017 study in Emerging Infectious Diseases covering 2009 to 2014. It reflects a within-category comparison across dairy products only, finding that raw milk and raw cheese were responsible for 96% of illnesses from contaminated dairy. It does not position raw milk against the broader foodborne illness landscape.
California offers a long-term production-scale baseline. A 2026 review published by the American Council on Science and Health reported that over the past 20 years in California, there have been no raw milk-related deaths, annual illness rates have remained below 0.45 per 100,000 servings, and in 12 of those 20 years no illness was reported at all in connection with raw milk consumption in the state, despite steadily increasing production.
Summary
The claim that raw milk legalization increases illness is rooted in real studies, but those studies measured raw outbreak totals rather than consumption-adjusted rates. When consumption is accounted for, the data show a declining illness rate coinciding with expanding legal access. The most recent longitudinal analysis, covering 2005 to 2020, found no statistical association between increased legalization and increased illness. The absolute burden of raw milk-related illness, placed against the full foodborne illness landscape, remains small relative to other commonly consumed foods.
