100A-8 |
Determination of the minimum leak size, under laboratory and commercial conditions, for bacterial entry into polymeric trays used for food packaging |
M. Pascall1, S. RAVISHANKAR2, N. Maks2, and H. Strassheim, III3. (1) Dept. of Food Science & Technology, Ohio State Univ., 2015 Fyffe Rd., Columbus, OH 43210, (2) National Center for Food Safety & Technology, Illinois Institute of Technology, IIT Moffett Campus, 6502 S. Archer Rd., Summit-Argo, IL 60501, (3) Land O'Frost, Inc., 16825 Chicago Ave., Lansing, IL 60438 The maintenance of commercial sterility of shelf-stable processed food is an important safety concern. In many cases, the package is the sole barrier to bacterial contamination. Knowledge of how this barrier could be compromised is essential to the food industry. This study sought to determine the minimum leak size for entry of Enterobacter aerogenesunder laboratory conditions, and normal flora under commercial conditions, into chicken noodles and beef enchilada packaged in 355mL PET/EVOH/PP trays. Channel leaks approximately 10 to 200µm in diameter (verified by microscopic measurements) were made across the sealing area of the test trays. Pinholes were made by imbedding laser drilled metal and plastic discs, with holes approximately 5 to 50µm, into the lid of the sample trays. Each tray contained one leak type. For the laboratory simulation, all trays were submerged and agitated for 30 minutes at 25oC in phosphate buffered saline solution containing 107CFU/mL E. aerogenes. Under commercial conditions, trays with channel leaks were processed in Truxton Still/steam/air and Loveless Water-cooked retorts until commercial sterility was achieved. All trays were subsequently incubated at 37oC for 2 weeks, then their contents were plated onto eosin methylene blue agar to determine the presence of any bacteria. All testing was done in triplicate. Under laboratory conditions, minimum pinhole sizes for E. aerogenes entry approximated 5µm (chicken noodles), 20µm (beef) for plastic discs, 40µm (beef) for metal discs, and 70µm for channel leaks (chicken) and 200µm for channel leaks (beef). Under commercial conditions, minimum channel leaks for bacterial entry approximated 50µm (chicken), and 200µm (beef). Average pH values for chicken and beef enchilada were 5.4 and 4.8, respectively. Results from this study showed that E. aerogenes can enter pinholes as small as 5µm under a worse case scenario. This information can be used to set pass/fail parameters for leak detection devices.
Session 100A, Food Microbiology: General II
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