Cutting Through the Propaganda on Raw Milk and Brucellosis

Various media have been waging one of the bigger anti-raw milk propaganda campaigns in memory through their reporting on a recent individual case of brucellosis attributed to raw milk consumption. The media are using the case of the third individual incidence of brucellosis blamed on raw milk consumption in the past year and a half to warn the public that people are putting their health in jeopardy if they don’t consume milk that is pasteurized. The illnesses occurred in Texas in August 2017, New Jersey in October 2017 and New York in November 2018 with the latest illness blamed on Miller’s Biodiversity Farm of Quarryville, Pennsylvania; there is currently a quarantine in effect prohibiting the farm from distributing raw dairy products. A cow that tested positive for Brucella has been removed from the dairy herd.

The media have been taking their cues from press releases issued by public health departments that have been giving the advice to pasteurize all milk. However, the solution to avoid getting brucellosis is far different from what public health and the media are telling you. In the words of one healthcare professional, “For public health officials to issue public notices that the solution to this avoidable problem is to pasteurize all milk, is astonishing.”

First off, the three cases of brucellosis are the only known cases attributed to raw milk consumption over the past 20 years. Brucellosis is a systemic disease in cattle and humans that is caused by the bacteria Brucella abortus. At one time the disease in cows caused severe reductions in offspring and was a problem for the cattle industry. A national eradication campaign was launched in the 1950s and, according to USDA statistics, the number of cattle/bison herds affected by brucellosis in the U.S. has been less than 10 every year from 2003 onward.1

The eradication program’s success has led to a huge decline in the number of brucellosis cases in humans; estimates are that there are about 100 cases of human brucellosis per year in this country.2 In the U.S. this is mainly an occupational disease with most of the rare cases of brucellosis being in people who attended the birth of an infected cow and then became infected during handling of the birth tissues and fluids.3,4

In an infected dairy cow, the Brucella abortus pathogen can proliferate in the mammary glands and then enter the milk. The pathogen can pass to humans when drinking the infected milk but, as mentioned, the cases of brucellosis (also known as undulant fever) attributed to drinking raw milk in the U.S. are extremely rare.

The “milk ring test” is the traditional and commonly used method to screen dairy herds to detect any cows with brucellosis; the test is performed on the herd’s milk to check for the rare presence of Brucella antibodies.

Two vaccines against brucellosis have been developed for calves: the S19 vaccine and the RB51 vaccine. The S19 vaccine is effective but it has the disadvantage of causing testing for antibodies to become positive. The vaccine can make it difficult to distinguish between a vaccinated cow and an infected cow. The RB51 vaccine does not cause the antibody testing of cows to become positive but another problem arises with its use.

The RB51 vaccine must be administered to calves before they become fertile; a side effect is that, if a cow is given the RB51 vaccine when pregnant, it may actually cause an infection with the vaccine strain of Brucella in the vaccinated cow. It is, therefore, possible that if the RB51 vaccine isn’t given strictly according to the protocol, the vaccinated cow may become infected and may shed the pathogen (i.e., the RB51 strain of Brucella) into the milk.

Public health officials have found in all three cases of illness from brucellosis attributed to raw milk consumption, the strain of Brucella abortus discovered in the three individuals was the RB51 vaccine strain. In fact, in November 2017, the Pennsylvania Department of Agriculture sent a letter to licensed raw milk producers in the state advising them to stop immunizing cows from brucellosis with the RB51 vaccine.5

So the solution to preventing brucellosis in raw milk is not for producers to pasteurize the milk but rather to either stop giving their herd the RB51 vaccine or to make sure their vets give the calves the vaccine before the calves become fertile. Worth noting, too, is that hundreds of people drank raw milk produced by the herds responsible for the three cases of brucellosis and, as far as is known, no one else became sick.

In the meantime, the media fear-mongering continues on. The latest case of brucellosis attributed to raw milk consumption dates back to November 2018, but to read the stories in the media, you would have thought it was just discovered. CDC press releases on this latest case dated January 23, 2019, and February 11, 2019, are providing the impetus for the flood of media reports.

Has an agenda ever gotten so much mileage over three illnesses?

A fear-inciting statement from the February 11 CDC press release that the media have parroted is, “the CDC and state health officials are investigating potential exposures, to Brucella strain RB51 in 19 states, connected to consuming raw (unpasteurized) milk from Miller’s Biodiversity Farm in Quarryville, Pennsylvania.”6 (The farm allegedly distributed raw milk to people in the 19 states listed later in the release.) Being exposed to a pathogen is far different than being sickened by it; we are exposed to various pathogenic bacteria such as listeria and e. coli in the environment every day.

One headline screamed, “Deadly Disease Caused by Raw Milk Has Already Put 19 U.S. States on High Alert.”7 There have been no deaths from brucellosis attributed to raw milk consumption since the eradication program succeeded in substantially eliminating the incidence of the disease and possibly even long before then.

The public health agencies and their allies in the press have been misleading the public long enough on raw milk and brucellosis. It’s time for fear and hysteria to give way to science and common sense.

1 “Brucellosis Affected Cattle/Bison Herds by State, FY 1997-2018” graph [PDF]. USDA-APHIS National Brucellosis Eradication Program (September 10, 2018),

2 “Facts About Brucellosis” [PDF]. USDA-APHIS National Brucellosis Eradication Program, Section “Resources” link (see question #21),

3 “How Brucellosis is Spread” section. USDA-APHIS National Brucellosis Eradication Program (September 10, 2018) [PDF],

4 “Fast Facts: Brucellosis, Undulant Fever” [PDF]. Iowa State University, The Center for Food Security & Public Health. April 2008,

5 Letter dated November 30, 2017 [PDF]. Pennsylvania Department of Agriculture, Bureau of Animal Health and Diagnostic Services, Dr. David Wolfgang (Director) and Dr. Lydia Johnson (Director, Bureau of Food Safety & Laboratory Services); accessed at

6 Media Statement [PDF]. CDC (February 11, 2019),

7 “Deadly Disease Caused by Raw Milk Has Already Put 19 U.S. States on High Alert” [PDF]., Carly Cassella (February 15, 2019),