Alice Catherine Evans and the Safety of Dairy Products


Alice Catherine Evans was an outstanding microbiologist who made one of the most medically important discoveries of the 20th century. She is well-recognized for establishing that humans are infected by the once-common, painful disease brucellosis from raw cow and goat milk. Brucellosis, a recurrent disease also known as Malta or undulant fever, causes shooting pain in the joints, fever, and depression. For years, her research findings and results were scorned and ignored because of her gender and because she did not have a doctorate degree. She lobbied successfully for the pasteurization of all milk and lived to see the disease fall into obscurity.

Born in 1881, on a farm in Pennsylvania, Evans worked as an elementary teacher for four years, because she could not afford to attend college. When a free course on nature was offered to rural teachers at Cornell University, Evans took advantage of the opportunity. While taking the course, she also took a basic course in the Agricultural College, which initiated her interest in bacteriology. Evans won a scholarship to Cornell and received a bachelor’s degree; then she received the first scholarship offered to a female from the University of Wisconsin, where she obtained her Master’s of Science degree.

In 1910, Evans became one of the first women scientists to hold a permanent position at the US Department of Agriculture Bureau of Animal Husbandry. She joined the dairy division, researching the bacteriology of milk and cheese. From her studies, she identified a bacterial infection carried by cows that could cause undulating fever in humans and published her findings in 1918. Researchers, veterinarians, and physicians were skeptical of her claim because they did not think that a female, particularly one without a doctorate degree, could have made such an important discovery. Dairy workers made fun of her warning that raw milk should be pasteurized to prevent people from developing disease.

However, in the late 1920s, Evans’ theories about brucellosis and raw cow’s milk were starting to become accepted internationally; microbiologists from Austria, Germany, Holland, Italy, and Tunisia positively confirmed her findings. Evans expanded her research to include studying the blood of people suffering from brucellosis. Finally, Evans’ assertions were accepted and pasteurization—heat treating milk to kill potential disease-harboring bacteria—became standard practice in the American dairy industry.

By the 1930s, the Government enacted milk pasteurization laws; Evans discovery, thus, saved countless people’s lives and health. Due to the pioneering work of Evans, brucellosis was understood not only as an occupational hazard for farmers but also as a threat to the food supply. Once the American dairy industry reluctantly accepted the necessity of pasteurization of milk, the incidence of brucellosis declined. In recognition of her achievement, in 1928 the Society of American Bacteriologists elected Evans as the organization’s first female president.

Evans was herself infected with undulant fever in 1922, and suffered from recurrent bouts for thirty years; she went through periods of illness and remission because the disease never left her system. However, this did not stop her from working throughout her life as a widely respected scientist. After leaving the Department of Agriculture, Evans worked for the US Hygienic Laboratory where she made valuable contributions in the field of infectious illness, including meningitis and streptococcal infections.

After retiring in 1945, Evans lectured widely to women about career development and encouraged women to pursue scientific careers. Evans passed away on 5 September 1975.


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