Dr. Mary Pennington held the position of chief at the food research laboratory within the United States Department of Agriculture. With America’s recent entry into World War I, occurring six months before the Illinois conference, Mary embarked on a mission to rally farmers to bolster shipments of poultry, eggs, and fish. “The supply of beef is insufficient, necessitating supplementation with other food sources,” reported the October 19, 1917, edition of the Leavenworth Times, quoting Dr. Pennington. “We must sustain our troops in the trenches and support our allies’ forces. Additionally, we must ensure ample provisions for our own civilian populace and that of our allies.”
Mary Pennington: The Creator of the Modern Refrigerator Boxcar
Although Mary’s objective was clear, the logistical challenge of transporting perishable goods across the country without spoilage remained unresolved. Over the subsequent six years, she dedicated herself to collaborating with railroad companies in refining the modern refrigerator boxcar.
Born in 1872 in Nashville, Tennessee, Mary Engle Pennington hailed from a Quaker family that provided unwavering support and fostered her academic pursuits. Her fascination with chemistry was evident from an early age. Early in her life, she harbored the ambition of pursuing a career in her chosen field. In 1890, she commenced her academic journey at the University of Pennsylvania in Philadelphia with aspirations of attaining a degree in science, a domain where female enrollment was still a novelty. Despite the university’s policy of not conferring degrees upon women, Mary diligently completed her coursework, demonstrating exceptional proficiency across all subjects. Recognizing her achievements, the school authorities awarded her proficiency certificates in chemistry, zoology, and botany. Undeterred, Mary continued her scholarly pursuits, earning the admiration of the board of trustees, who conferred upon her an advanced PhD in 1895.
Between 1897 and 1899, she delved into research on physiological chemistry at Yale University. Before concluding her tenure at this esteemed institution, she assumed the role of director at the clinical laboratory of the Women’s Medical College of Pennsylvania. Concurrently, she served as a bacteriologist with the Philadelphia Bureau of Health and contributed her expertise to the Pennsylvania Department of Hygiene. Her efforts during this period notably improved sanitation practices concerning milk and its by-products.
Mary’s groundbreaking research on bacterial toxicity levels in dairy products attracted the attention of Harvey Wiley, a prominent chemist and head of the US Department of Agriculture, who advocated for stringent food safety standards. Recognizing Mary’s expertise, Wiley invited her to join his “poison squad,” a team of dedicated scientists committed to ensuring the purity of consumables. Mary’s profound understanding of agricultural products in cold storage proved invaluable to the department. Together, their discoveries catalyzed the enactment of the Pure Food and Drug Act of 1906, which mandated transparent labeling of ingredients and banned harmful additives.
Following the legislation’s passage, Dr. Wiley appointed Mary to lead the Bureau of Chemistry’s Food Research Lab. Aware of potential prejudices, he submitted Mary’s credentials under the pseudonym M. E. Pennington for civil service consideration. Despite initial skepticism, Mary secured the position and spearheaded efforts to enforce the Pure Food and Drug Act. Under her guidance, the laboratory conducted pioneering research that demonstrated the prolonged freshness of perishables under refrigeration.
In a pivotal presentation to the Warehousemen’s Association in Washington, DC, in 1908, Mary emphasized the significance of immediate fruit cooling post-harvest and cautioned against freezing food products due to resultant chemical alterations. She advocated for meticulous butter manufacturing and highlighted the importance of proper transportation. Mary showcased a cold-storage boxcar, developed under the Agricultural Department’s auspices, designed to maintain fruits at optimal temperatures during transit. Scheduled for testing in fruit groves, this innovation promised to revolutionize food distribution.
The introduction of refrigerated boxcars, colloquially termed “reefers,” dates back to the late 1860s. Initially featuring metal racks suspended over ice and salt mixtures, these early designs evolved over time, incorporating improvements such as enhanced insulation and ventilation to ensure the preservation of perishable goods during transportation.