Lloyd Hall

Lloyd Augustus Hall (June 20, 1894 - January 2, 1971) was an African-American chemist who contributed to the science of food preservation. By the end of his career, Hall had amassed 59 United States patents, and a number of his inventions were also patented in foreign countries.

Early life

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 do most of his work in food science.

Major works

Hall devoted much of his efforts to the technologies behind curing meat, particularly to improving a curing salt marketed by Griffith Laboratories, known as Prague Powder. This product originated with German chemist Karl Max Seifert, developer of a process whereby solutions of sodium chloride and one or more secondary salts were sprayed onto hot metal and rapidly dried, producing crystals of the secondary salts encased inside a shell of sodium chloride. Seifert patented the process in 1934 and sold the rights to Griffith Laboratories.[1] (http://patimg2.uspto.gov/.piw?Docid=01950459&idkey=NONE) The adaptation of this process specifically for meat curing was then patented by company owner Enoch L. Griffith who proposed nitrates and nitrites, well-known curing agents, as the secondary salts.[2] (http://patimg1.uspto.gov/.piw?Docid=02054624&idkey=NONE) Although Lloyd Hall did not "invent" this product as is commonly thought, and never claimed to have done so, he took the lead role in its further development, adding hygroscopic agents such as corn sugar and glycerine to inhibit caking of the powder. Most of his patents in meat curing dealt with either preventing caking of the curing composition, or remedying undesired effects caused by the anticaking agents.

Hall also investigated the role of spices in food preservation. It was commonly known that some seasonings had anti-microbial properties, but Hall and co-worker Carroll L. Griffith found that some spices carried many bacteria, as well as yeast and mold spores. To counter these problems, they patented in 1938 a means to sterilize spices through exposure to ethylene oxide gas, a fumigant. Ethylene oxide is still used for spice sterilization in some countries, but health concerns led to its being banned for this purpose in the European Union and Japan. Hall and Griffith later promoted the use of ethylene oxide for the sterilization of medical equipment,[3] (http://patimg1.uspto.gov/.piw?Docid=02189947&idkey=NONE) advancing an idea that had been around for at least a few years.[4] (http://patimg1.uspto.gov/.piw?Docid=02075845&idkey=NONE)

Hall invented new uses of antioxidants to prevent food spoilage, especially the onset of rancidity in fats and oils. Aware 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.

Humanitarian activity

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.