Critical Clues from Clams

By age 25, Prescott, with Underwood, had completed his seminal work, which was never patented. Goldblith called Prescott one of the foremost basic and applied bacteriologists of his day. Prescott worked with R.S. Breed on the direct microscope count of milk, an advancement still used today that allows rapid determination of bacterial counts before a milk tanker truck is unloaded. His bacteriological work on food, milk, and water led to his election as president of the Society of American Bacteriologists. Furthermore, his work on water supplies, sewage purification, and public health education helped him to become president of the American Public Health Association. In 1929, he was elected chairman of the MIT faculty, and in 1932 he became MIT’s first dean of science.

Goldblith called him a renaissance man who enjoyed good literature and “was himself a writer of considerable talent.” He relaxed by fishing with friends, including Underwood, and writing poetry. His research interests ranged from basic and applied microbiology to the chemistry of coffee, from banana plant diseases to refrigerated and frozen foods, and from sanitation to the dehydration of foods.

Prescott formed two outside laboratories and served in both world wars. In WWI, he served as a major in the Sanitary Corps in charge of dehydrated food production and sanitation. In WWII, he was special consultant to the quartermaster general and author of a history of Army rations from 1775 to 1940.

At MIT, he took two semesters each of French and German, which proved useful in 1900 when he spent five months in Berlin and Copenhagen learning new techniques in industrial biology. After graduation, Prescott spent several months in Worcester, Mass., as assistant chemist and biologist at the Sewage Purification Works, then returned to Boston in 1895 to become private assistant to Sedgwick, his mentor, at a salary of $800 a year.

In October 1896, he became an instructor in biology at MIT. He kept working with Sedgwick on bacteriological contents of certain ground waters, especially deep wells; on the influence of variation of culture medium upon the development of water bacteria; and on the typhoid fever epidemic in Marlborough, Mass., apparently caused by infected skim milk—the first case of its kind reported in America, according to the 26th Annual Report of the Massachusetts State Board of Health. Also in that year, Prescott started his research program with Underwood.

1903 was a watershed year for Prescott: He was promoted to assistant professor of industrial microbiology with a salary of $1,200, up from the $1,000 he was then making as an instructor, according to Goldblith. In 1909, he was promoted to associate professor.

Advances in Microbiology

In his 1951 acceptance speech for IFT’s Stephen M. Babcock Award, Prescott described the state of food safety when he first started studying, saying: “In the period before 1890, food chemistry was in its callow youth. It consisted chiefly of the search for not uncommon adulterants in milk and in many food adjuncts and in the proximate analysis of foods into fats, carbohydrates, and nitrogenous substances. Nutrition in the modern sense was in a very underdeveloped status. Enzymes as we know them today were a mystery, and vitamins entirely unknown. Organic chemistry gave no broad vistas of syntheses of products having a direct relation to health.”

In 1895, Sedgwick handed Prescott the project that brought him to Underwood, his first real research partner, who Prescott would later say was closer than a brother. In an unpublished paper titled “How Food and Technology Developed at MIT,” Prescott described his work with Underwood:

“For many months we spent afternoons and evenings in experimental work at the laboratory, and eventually solved the problem. We found in the fresh material used, the clams, the most resistant spore-forming bacteria I have ever encountered. … The sterilization process most commonly employed in those days was by heating in an open water bath, although steam sterilization was also available and used by the firm. Factory operators in those days, however, knew nothing of the causes of spoilage, and had no clear idea of the relations of time, temperature, and pressure, so sterilization was largely a matter of luck. As a result, losses in canning throughout the country were enormous, in some cases a complete season’s pack of corn or peas being a total loss.

“By many trials we found that our resistant germs from clam stomachs could be boiled continuously for 24 hours and still survive, and we stayed up several nights to maintain the processing for this period. Incidentally, this gave us a practically pre culture of the cause of the damage. Using these bacteria and similar material or pure cultures derived from the spoiled cans, we found that under steam sterilization at 15 pounds pressure (250 degrees F.) the spores could be killed in 10 minutes, although resisting 212 degrees for 24 hours. By resorting to steam sterilization at this pressure for the requisite time the trouble for the company was entirely prevented. But this work led us on to study and establish time-temperature relations for many other products, especially vegetables and fish and for three years we worked at canning plants during the packing season. We continued this work for five years.”

Goldblith noted that Prescott and Underwood continued their partnership and friendship until Underwood died in 1929. Underwood, a self-educated man, had been a lecturer without salary in MIT’s Department of Biology.