Science Fair Project Encyclopedia
Lloyd Augustus Hall (June 20, 1894 - January 2, 1971) was an African-American chemist who greatly advanced the science of food preservation. He is responsible for the preservatives, meat curing products, seasonings, emulsions, bakery products, antioxidants, protein hydrolysates, and the many other products that keep our food fresh and flavorable. By the end of his career, Hall had amassed over 100 patents, and the preservation techniques and chemical preservatives he invented are still in use today.
Lloyd Hall was born in Elgin, Illinois. His father was a Baptist minister, Lloyd's grandfather was one of the first black preachers at the church his father ministered. After attending high school in Aurora, Illinois, he earned a bachelors degree in chemistry from Northwestern University.
With the onset of the United States' involvement in World War I, he was commissioned as a lieutenant and explosives inspector in the Ordnance Department. However, he found himself at the receiving end of a variety of discriminatory practices in the military and requested transfer. Over the next nine years, he worked for several chemical laboratories, frequently as a consultant, until in 1925 he was hired by Griffith Laboratories , where he would make his major contributions to food science.
Hall devoted much of his efforts to the technologies behind curing meat. While the use of salts such as sodium chloride and sodium nitrate in food preservation is ancient, prior to his work, it was poorly understood and was frequently a hit-or-miss process balanced between ineffective preservation and negative impact on flavor. Hall developed a process whereby solutions of sodium chloride, sodium nitrate, and sodium nitrite were sprayed onto hot metal and rapidly dried, producing crystals of the nitrates and nitrites encased inside a shell of sodium chloride. These flash-dried salt crystals proved effective at reliably preserving meat without adversely affecting taste. Hall also pioneered the use of glycerine to stabilize salts in meat, allowing the preservatives to remain within the meat rather than forming a crust on the outside.
He also investigated the role of spices in food preservation. It was commonly held that seasonings were effective preservatives, but Hall found that rather than preserving food, they generally only covered up the taste of spoilage. In fact, seasonings frequently accelerated spoilage because they contained bacteria and mold spores. To counter these problems, Hall developed a means to sterilize spices through exposure to ethylene oxide gas. Later, he promoted this same method for the sterilization of medical equipment, and it has become a standard method for sterilizing medical supplies made of plastic or other materials that could be damaged by the high temperatures used in other sterilization techniques.
Hall introduced the use of antioxidants to prevent food spoilage, especially the onset of rancidity in fats and oils. Upon determining that unprocessed vegetable oils frequently contained natural antioxidants such as lecithin that slowed their spoilage, he developed means of combining these compounds with salts and other materials so that they could be readily introduced to other foods.
After retiring from Griffith in 1959, Hall consulted for the Food and Agriculture Organization of the United Nations. From 1962 to 1964, he sat on the American Food for Peace Council . He died in 1971 in Pasadena, California.
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