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J. TANG1, T. C. S. Yang2, C. P. Dunne2, G. Wooddell3, F. Liu1, B. O'Hagan4, J. Lucken5, M. H. Lau6, and E. J. Turek6. (1) Biological Systems Engineering, Washington State Univ., Pullman, WA 99164-6120, (2) U.S. Army Natick Soldier Center, U.S. Army Research, Development and Engineering Command, Combat Feeding Innovative Science Team, Kansas St., Bldg. 36, Rm. E-108, Natick, MA 01760-5020, (3) Eval Company of America, Suite 300, Two Corporate Plaza, 2625 Bay Area Boulevard, Houston, TX 77507, (4) Graphic Packaging, 160 Washington Street, Menasha, WI 54952, (5) Rexam Containers, 710 West Park Road, Union, MO 63084, (6) Strategic Research, Kraft Foods, Inc., 801 Waukegan Rd., Glenview, IL 60025 Retorting is the most frequently used processing method in commercial production of shelf-stable low acid (pH>4.5) foods. Retorting systems rely on conventional surface heating and internal conduction to kill anaerobic spores in packaged foods to make them free from pathogenic and most spoilage bacteria. The high processing temperatures (120-130o C) and relatively long processing times (30-100 min) used in those processes often cause severe degradation in the processed food and certain degree of thermal damage in the package materials and foods within. Emerging food processing technologies that use volumetric heating through MicroWaves (MW) or Radio Frequency (RF) energy hold promise to produce high quality shelf-stable foods. MW and RF heating is a result of the polarization effect of electromagnetic radiation on foods at frequencies between 10 MHz and 300 GHz. MW and RF energy interacts directly with foods to generate heat in hermetically sealed polymeric containers, thus can significantly reduce process times. These new sterilization technologies create new challenges and also opportunities for food packaging, especially related to flexible pouch films and lid-stock films for polymeric trays. For example, laminated aluminum foil or metallized films usually would shield electromagnetic fields from reaching food in packages and are not suited for microwave sterilization processes. However, strategically designed metallic shielding in polymeric packaging might increase the uniformity of MW or RF energy distribution, and further improve the food quality. Also, shortened processing times in microwave sterilizations may create opportunities for developing EVOH-laminated barrier package films because of the reduced gas ingress and moisture migration into packaging materials during processing. In this presentation, we will discuss unique process requirements for packaged foods associated with MW and RF sterilization technologies. We will discuss challenges, which include geometric limits not found in conventional processing, and possible solutions for flexible package materials.
Session 39, Advances in packaging technology required for implementation on novel food processes
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |