Storage and shipping innovator wins World Food Prize

Photos Courtesy of the World Food Prize Foundation.
Phillip Nelson’s lengthy career at Purdue involved ongoing food processing, packaging and transportation research.

Dr. Phillip E. Nelson was awarded the 2007 World Food Prize in October of last year. His research has greatly improved storage and transportation of fresh fruits and vegetables.

The World Food Prize Foundation awards the international honor annually to people who have made significant contributions to its goals of improving the quality, quantity and availability of food across the globe. Winners have included professionals in agriculture, marketing, nutrition and related areas. Nelson is the first in the food science field to be presented with the $250,000 prize.

Growing an innovator

Although Nelson’s 46-year career was spent primarily in teaching and research at Purdue University in West Lafayette, Ind., he has firsthand knowledge of the challenges growers face. He grew up on a 500-acre Indiana farm, working in tomato fields and in the family’s tomato canning plant, the Blue River Packing Company. At the age of 15, he was named the “Tomato King” in a 4-H competition sponsored by Purdue’s extension service. He went on to earn an agriculture degree at Purdue and began his career as Blue River’s manager.

The tomato industry transitioned to the West in the late 1950s and early 1960s, leading to the demise of the packing company and sending Nelson back to Purdue. He was arbitrarily placed as a teaching assistant in the horticulture department, a field he came to love. He completed a Ph.D. in 1967 with a dissertation on the volatility of flavors in canned tomatoes. Nelson planned to work in the private sector, but a chance encounter with Purdue dean and future U.S. Secretary of Agriculture Earl Butz opened the possibility of an academic career. His working life was to be spent at his alma mater.

Love of tomatoes benefits growers

From his experience in growing and processing tomatoes, Nelson knew there was room for improvement in preservation techniques. His early research focused on developing methods to reduce postharvest spoilage, working with and expanding upon the aseptic processing technique developed in the 1940s. He investigated and implemented a system for storing tomatoes aseptically (pathogen-free) in tanks at an ambient temperature for extended periods without becoming contaminated or spoiling. Enormous carbon steel tanks (initially 100-gallon tanks and eventually increasing in capacity to 8 million gallons) that are coated with epoxy resin and have sterilized valves and filters allow tomatoes, and other food products, to be stored and removed without reintroducing contaminants. The result is that large quantities of a product can be stored past harvest and processed periodically throughout the year into various products (sauces, juices, ketchup, etc.). The technique also means that food can be transported in a safe manner around the world. This achievement greatly benefited the tomato industry by making the crop less seasonal; now, more than 90 percent of all tomatoes harvested worldwide are aseptically preserved for later processing into a variety of products.

The process also maintained and perhaps improved the nutritional content and flavor of the final product. Nelson achieved successful aseptic processing by combining past research with his own investigation and development. The Institute of Food Technologists (IFT) rated aseptic processing and packaging as the top innovation in the field in a 1991 assessment of food technology.

Aseptic processing involves sterilizing the food and the container; the finished product in its container remains sterile and is shelf-stable. The food is passed through a narrow pipe where it is quickly heated to kill pathogens, and then rapidly chilled. The short heating time is adequate to destroy germs without affecting the food’s quality. That is a significant improvement over canning, which requires a lengthy heating process that compromises the flavor.

By working hand-in-hand with equipment manufacturers to design and build the tanks, valves, filters and flexible bag containers for storing processed food, Nelson helped the fruit and vegetable industry expand into creating food products year-round. For example, bulk aseptic storage and transportation have made possible the widespread distribution of not-from-concentrate orange juice. These advances brought new products to the marketplace, greater stability and shelf life of food products, and general longevity in the food supply.

An important outcome is a new ability to help feed undernourished people across the globe. Nelson has traveled extensively to assist developing nations create ways to process and transport foodstuffs for their citizens, as well as for export.

Related innovations

Nelson’s work has many applications. He discovered an effective method of sterilizing huge containers, such as 300,000 to 500,000-gallon vats in ships, allowing massive quantities to be transported. But, not all his work is implemented on such large scales; he had a hand in creating the individual sealed bags that store everything from yogurt to wine. Other innovations in which Nelson had a part include:

Dr. Nelson helped develop safe methods of transporting large quantities of food via ship.

• Designing and constructing aseptic valves for the large containers, preventing microorganisms from moving through the valve stem into the sterile environment;

• Refining a system for smaller-scale, in-bag storage (1 gallon to 300 gallons), allowing processors to fill multilayer, inexpensive sterile flexible packaging material with aseptically processed products;

• Perfecting a membrane for the aseptic bags that is ruptured during the fill, then resealed with a sterilized foil cap, which prevents recontamination; and

• Increasing the capacity of bulk bag-in-box technology up to 3,000-gallon capacity for cost-effective shipping of processed food.

Impact on growers

The revolution in food storage and transportation brought many opportunities for fruit and vegetable growers. The extended life of produce increased the demand, allowing growers to sell to processors in addition to fresh markets. Perhaps the best news for U.S. farmers is that this country has only scratched the surface of applications of the aseptic process. In Europe, for example, a much greater variety of products use aseptic packaging.

“Dr. Nelson’s work has transformed the global food industry and has allowed entrepreneurs to build successful businesses that use crops raised by farmers,” said Purdue President France A. Córdova. “He is an outstanding example of the power of a university to turn discovery into benefits for others.”

The author is a freelance writer based in Greensboro, N.C.

Resources for Aseptic Processing and Packaging

The Aseptic Packaging Council:
Tetra Pak:
American Copak:
National Food Laboratory: