Hall introduced chemical innovations that helped change the way we store andpreserve foods today, including the now-universal use of nitrates in place ofsalting to cure meats. Born in 1894 in Elgin, Illinois, Hall attended Northwestern University and the University of Chicago, where he majored in chemistry. At Northwestern, Hall befriended classmate Carroll L. Griffith, in whose Griffith Laboratories he would later spend the most productive years of his career. Hall was also one of the first African-Americans to overcome the barriers of discrimination in science and technical careers. Rejected on the firstday at his first job at Western Electric Co.--after being hired over the telephone--with the blunt declaration, "We don't take niggers," Hall took a position with the Chicago Department of Health Laboratories as a chemist in 1916.
Hall soon developed an interest in the burgeoning applications of chemistry to food processing. In 1925, as a senior chemist at Griffith Labs, Hall beganwork on the chemical preservation of meat. Until then, salting, with sodium chloride or table salt, had been the primary, though unsatisfactory, means ofcuring meat. Although chemists knew that nitrate compounds, combined with salt, preserved the color and appearance of meat better, the compounds also tended to penetrate meat too fast, causing the meat to disintegrate. Hall deducedthat if the nitrate could be combined with the salt at the crystal level, itwould allow the two substances to penetrate at the same speed. He eventuallyhit upon the technique of flash drying. By quickly drying a solutionof sodium chloride and nitrate compounds over hot rollers, the dried substance formed a salt crystal with nitrate at its center.
Hall later turned his attention to the sterilization of spices, cereals, andcondiments, which, untreated, can host bacteria, yeasts, and spores, thus contaminating food. The conventional method of food sterilization--killing microorganisms with heat--would burn the spices and make them unpalatable. Hall decided to tackle the problem through chemical means, eventually discovering that ethylene oxide gas--formerly used as an insecticide--was effective not only in sterilizing spices, but also as a sterilizer for medical instruments andmedicines, an application in which the gas is still used today.
February 11, 2004: It was announced that Hall will be inducted into the National Inventors Hall of Fame for his discoveries and inventions relatedto food preservation. The induction ceremony will be held on May 1, 2004, inAkron, Ohio. Source: National Inventors Hall of Fame, www.invent.org,April 8, 2004.