Defining and Monitoring Seal Integrity - the Key to Advances in Plastics Packaging, 1996 Polymers, Laminations & Coatings Conference Proceedings

Food processors who pack in semi-rigid and flexible packaging would like to achieve the same level of sterility maintenance assurance as has been achieved for cans, but the current equipment for leak detection is expensive, efficiency levels are far from 100%, and detectable leaks have not been related to probability of subsequent contamination. Just as package integrity was key to the whole concept of canned thermally processed foods, so will package integrity be to the market for fresh and processed foods packaged in plastic. Hermetic seal is the critical component in package integrity. For most plastic packages, hermetic seal is achieved by some form of heat. The properties of heat seals and how these properties affect packaging performance will be discussed. Suppliers of heat seal monitoring equipment are marketing any number of non-destructive devices, both on- and off-line, that are based on sound technological concepts, but none offers an effective, efficient, on-line, 100% dud-detection device. Factors impeding progress in non-destructive device design include matching a technology to the package application, assessing the minimum defect dimension acceptable to the processor, and coping with high speed packaging lines. These factors will be discussed in terms of the knowledge base today and designing for tomorrow.