Outbreak Studies

CDC has conducted three studies that show an increase in the number of raw milk–associated outbreaks as more states have allowed the legal sale of raw (unpasteurized) milk. These studies indicate that outbreaks linked to raw milk continue to threaten the public’s health. You should only consume pasteurized milk and milk products. Look for the word “pasteurized” on product labels

Foodborne Illness Outbreaks Linked to Unpasteurized Milk and Relationship to Changes in State Laws – United States, 1998–2018

The newest study reports the number of outbreaks and outbreak-associated illnesses linked to raw milk over time. The article also compares those numbers in states where the sale of raw milk is legal to states where it is prohibited.

The study found that the number of outbreaks linked to raw milk has increased over time.

  • From 1998 through 2018, 202 outbreaks occurred because of drinking raw milk. These outbreaks caused 2,645 illnesses and 228 hospitalizations.
  • Among illnesses linked to unpasteurized milk that occurred from 2013 through 2018, 48% (325) were among people aged 0–19 years.
  • Areas where raw milk was legally sold had 3.2 times more outbreaks than areas where the sale of raw milk was illegal. Areas where raw milk was allowed to be sold in retail stores had 3.6 times more outbreaks than areas where sale was allowed only on farms.
  • The study shows laws that increase the availability of raw milk are associated with more illnesses and outbreaks.

Read the study

Increased Outbreaks Associated with Nonpasteurized Milk, United States, 2007–2012

This study reviewed outbreaks linked to raw milk in the United States. The study analyzed the number of outbreaks; the legal status of raw milk sales in each state; and the number of illnesses, hospitalizations, and deaths associated with these outbreaks.

More states are legalizing the sale of raw milk even though this leads to an increase in the number of outbreaks.

  • From 2007 through 2012, 26 states reported 81 outbreaks linked to raw milk. The outbreaks caused 979 illnesses and 73 hospitalizations.
  • The average number of outbreaks linked to raw milk each year was four times higher from 2007 through 2012 than from 1993 through 2006.

Read the study

Nonpasteurized (Raw) Dairy Products, Disease Outbreaks, and State Laws—United States, 1993–2006

The earliest study reviewed outbreaks linked to dairy products. The study compared outbreaks linked to raw (unpasteurized) dairy products and outbreaks linked to pasteurized dairy products in terms of the types of infection; the numbers of outbreaks, illnesses, hospitalizations, and deaths; and age and sex of the ill people in the outbreaks. This study also compared the number of outbreaks linked to raw dairy products in states that allowed the sale of raw dairy products to the number in states that prohibited the sale of these products.

  • From 1993 through 2006, 121 outbreaks were linked to dairy products identified as pasteurized or unpasteurized (raw). These outbreaks resulted in 4,413 illnesses and 239 hospitalizations.
  • 73 of these outbreaks were linked to raw milk, and 48 were linked to pasteurized milk.
  • If you consider the number of outbreaks associated with raw milk in light of the very small amount of milk that is consumed raw, the risk of outbreaks linked to raw milk is at least 150 times greater than the risk of outbreaks linked to pasteurized milk.

Read the study