PENNINGTON, Mary, née Engle, American microbiologist, 1872-1952. She developed milk and dairy inspection standards, and procedures for dairy herds. In time, the procedures she developed were adopted nationally. Mary also invented a new type of egg-packing case, that reduced egg breakages by 5-10%. In the 1940s she introduced a new method of killing chickens, so that the feather-plucking became easier. The benefits of transporting chickens live was made clear to the authorities, there was less chance of human infections as a result. Mary developed the concept of freezing chickens and poultry immediately after killing, i.e., before packing for refrigerated transport. Ultimately this proved safer for the consumer. An expert in refrigeration of dairy products and related issues.