Oxygen Ingress in Plastic Retortable Packages during Thermal Processing and Storage

The influence of thermal processing and storage conditions on oxygen ingress in CPET and EVOH-containing PP retortable trays was investigated. Oxygen ingress during retorting was negligible in CPET trays, but increased in PP/EVOH/PP trays at higher retort temperatures, longer process times, and higher oxygen partial pressures. Hydration of EVOH-containing trays did not influence oxygen permeability during thermal processing, but was correlated to oxygen ingress during storage. Oxygen ingress in PP/EVOH/PP trays was minimal during one year of storage at 21. 1 0 C, 60% RH, but increased substantially after 100 d storage at 32.2 0 C, 75% RH. Oxygen ingress in CPET trays was greater than that of EVOH-containing trays during storage under both conditions studied.