Dr. Mary Engle Pennington

Refrigeration and frozen food pioneer

- Robyn Young

It was the beginning of the twentieth century. City households depended on the “ice man” to deliver blocks of ice to keep their perishable foods cold. On rural farms, tiny buildings called springhouses were erected over a running creek. These served as storage rooms for cans of milk, crocks of butter, and fresh eggs. The cool temperature of the water running through the bottom of the springhouse helped keep food from spoiling. Families did not enjoy the modern marvel of a refrigerator or freezer.

As urban populations increased, fewer people grew their own food or raised chickens at home. City dwellers depended on farmers for dairy, meat, and vegetables. However, buying fresh food was difficult. Farmers transported goods to market by train. Eggs, milk, and poultry often arrived damaged and spoiled. Shipping companies tried packing shipments with blocks of ice, but when it melted, the food sometimes got moldy. They tried covering food with moss, hay, and leaves to keep it cool for the long ride to the city. But there was no good fix. Thousands of people died every year from eating food that had gone bad on its way to market.

Chemist Mary Engle Pennington solved that problem. She was the greatest authority on refrigeration in the early twentieth century. Over the course of a 40-year career, Pennington changed the way Americans transported and stored food.

A Self-Made Scientist

Mary Engle Pennington was born on October 8, 1872. Her family moved from Nashville, Tennessee, to Philadelphia, Pennsylvania, shortly after she was born. The Pennington family lived in a brick house four blocks from the University of Pennsylvania.