Dr. Bruce Welt
With degrees in chemical engineering, food science and agricultural and biological engineering, Dr. Bruce Welt completed his education at the University of Florida with prominent food-process engineer, Dr. Art Teixeira. He then spent a few years in industry before returning to UF to help start the packaging science program. Welt's background gives him a broad view of his field, with the practicality of a working engineer and the insight of a researcher. He applies this balanced view in his research and in his teaching.
Welt's research focuses on plastics that are used for food packaging. He says that one of the most important issues in using plastics with food is called permeability, which measures the amount of oxygen that can pass through the plastic. Plastics are made of molecules which are long chains of repeating subunits. Electrical and mechanical forces hold the chains together, and that gives plastics their solid but often stretchy nature. There is room between these chains for small molecules to work their way through.
Permeability is not necessarily a bad thing. Welt explains that when broccoli or lettuce are harvested, it is like a cut flower, it is fresh and alive, but the clock is ticking. The goal of the farmer, distributor, and grocer is to get these products to the consumer in the freshest condition possible. Oxygen works both for and against this. Too much oxygen, and the products ripen too rapidy and may be in poor condition by the time they get the grocery shelf. Too little oxygen also causes rapid deterioration due to something similar to suffocation. An ideal amount of oxygen leads to longest preservation of quality. Researchers in this area of “modified atmosphere packaging” seek first to find the best oxygen level for each specific product, and then they seek package designs that will maintain that optimum level. Research in Welt's laboratory has been aimed at adjusting the properties of a common and inexpensive packaging material, polyethylene, so that its permeability toward oxygen can be set at just the right level.
Welt has also worked on food irradiation. Food safety is an important issue as the increasing numbers of consumers, products, and outlets meet new packaging materials and new pathogens. Food irradiation is a simple and practical approach that can increase that margin of safety. But there are important questions about how the energy that irradiation uses affects packaging in contact with foods when treated. With a new generation of packaging materials come a host of new questions about this interaction, and Welt is beginning to take on some of these questions.
- PKG 3103: Food Packaging
- PKG 4008: Distribution and Transport
- PKG 4101C: Computer Tools for Packaging
- PKG 4011: Packaging Production and Processing
- PKG 4905: Senior Design in Packaging Science
Research and Extension
- Gas permeation for modified atmospheric packaging applications (MAP)
- Irradiation of food contact materials
- Food-package interactions (migration, aroma scalping, moisture gain/loss, etc.)
- Track-and-trace system development and testing (RFID, vision systems, 2D barcodes)
- Distributed packaging-relational database applications prototyping
- Flexible package prototyping and leak testing