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From: Food Quality & Safety magazine, December/January 2012

Critical Clues from Clams

Samuel Cate Prescott and William Lyman Underwood made canned food safe

by Lori Valigra

When William Lyman Underwood (1864-1929) sought advice about swollen cans of food from Massachusetts Institute of Technology Professor William T. Sedgwick in late 1895, he planted the seed for research that would become the scientific underpinnings of canned food safety.

The William Underwood Company of Boston, America’s first canning company, was known for its deviled ham and packed a variety of foods using the principles of Nicolas Appert. (Known as “the father of canning,” Appert was a French confectioner who in 1820 discovered that heat and airtight bottles could preserve food; see “The Father of Food Preservation,” Food Quality, February/March 2011.)

However, Underwood, grandson of the company founder, discovered that canned food still frequently spoiled. Armed with swollen, stinking cans of spoiled clams, he collaborated with a promising protégé of Sedgwick’s named Samuel Cate Prescott (1872-1962). Working side by side daily for months, they found that heat-resistant microorganisms survived the food preparation process to cause the spoilage, even after the foods were canned.

Their discovery that the microorganisms could be killed in 10 minutes when boiled at 250 degrees F became a milestone in canned food safety and in Prescott’s career. He later went on to cofound the Institute of Food Technologists (IFT), the first body to recognize food science as a profession, and became its first president in 1939. Prescott also won the IFT’s second Nicolas Appert medal in 1943.

Sedgwick was so impressed by the work that he gave the two men credit in 1903 in MIT’s annual report for working out for the “first time the bacteriological aspects of the canning industry. By their investigations, Messrs. Prescott and Underwood have contributed materially to the improvement of the practical processes of canning and preserving foods. Professor Prescott has also discovered, and made known in a series of published papers, a remarkable similarity between the common intestinal bacteria and certain lactic acid bacteria, a discovery of the very first importance in the interpretation of sanitary bacteriological analyses of water and sewage.”

Prescott worked with R.S. Breed on the direct microscope count of milk, an advancement still in use 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.

Packaging consultant Aaron L. Brody, in a December 2009 article in the IFT’s Food Technology magazine, wrote about Prescott: “He had no known patents in his name. But Samuel Cate Prescott did more for canning than any person other than Nicolas Appert, who pioneered the process. Prescott and his colleague William Underwood provided the understanding of the role of biology in the thermal preservation of foods—the very foundation of a discipline we now proudly call food science.”

The achievement was made early in Prescott’s career, but he was already proving to be a star in research circles. Underwood’s main interest lay in photography, a skill that proved invaluable in documenting microorganisms during his research with Prescott on time-temperature canning.

Humble Beginnings

Prescott was born the only son of Mary Emily Cate Prescott and Samuel Melcher Prescott on a small farm. Biographer Samuel A. Goldblith, a former professor of food science at MIT and a student of Prescott’s, wrote that Prescott’s formal education started in one-room country schoolhouse in New Hampton, N.H. When he was 15, he served as the “rod man” for a small survey party laying out the border between eastern Massachusetts and New Hampshire. At 16, he entered Sanborn Seminary, a prep school in Kingston N.H., and attended the school for two years, graduating in 1890. He was a chemistry major at MIT from 1890-1894 and took a course in bacteriology that “fascinated him, and he wrote his senior research thesis on the subject of ‘Salts as Nutrients for Bacteria,’” Goldblith wrote.

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.

After finding the solution to his smelly canned clams, Underwood also worked pro bono with Prescott on the chemical dynamics of soured canned corn, a product the Underwood Company did not sell, wrote Genevieve Wanucha in a 2008 article for MIT’s Scope magazine entitled, “Two Happy Clams: The Friendship that Forged Food Science.” The duo decided they needed to study corn at the point where spoilage began, when it was peeled from the husk. They set up shop in an empty factory in Oxford, Maine, near cornfields, where they improvised with a makeshift incubator. “Cans of corn heating in this creation exploded often, spraying yellow mush onto the factory floor as they worked and slept,” Wanucha wrote.

Underwood took plenty of slides of the newly discovered organisms. Wrote Wanucha, “The March 1898 issue of Technology Quarterly boasted photographs printed on glossy white paper of actual-size petri dishes filled with circular spidery blooms of bacillus, each like a telescopic glance at a pockmarked moon.”

The two men traveled to Buffalo, N.Y., in February 1898, to present their canned corn findings at the Atlantic Trade Packers Association meeting, where they reported that bacterial blooms could be canned safely after being scalded for 55 minutes. The researchers then expanded their work to canned peas, tomatoes, spinach, sardines, and lobster meat.

Their work transcended mere scientific exploration, Wanucha wrote. “Their academic heirs at MIT later reminisced that these two men found in food science a way to engage their love of the natural world, not only because they could seek out the hiding spots of pathogens in cornfields and fjords, but because they could spend their free time fishing and photographing their trips. But this friendship stood for more than an enthusiastic dedication to their job. Their discoveries established the field of food science and technology at MIT—and quite charitably. Prescott and Underwood never took out (what would have likely been) a very profitable patent on their thermal-canning processes.”

BIO

Valigra is a freelance writer based in Cambridge, Mass. Reach her at lvaligra@gmail.com.

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