The objective of this study was to determine how hole diameter, channel length, test organism motility, concentration and aerosol exposure time affected microbiological contamination of sealed flexible pouches. Nickel microtubes with 10 μm and 20μm hole diameters and lengths of 5 mm and 10 mm were used in various combinations to create seal defects in 128 retortable pouches. A 119,911 cm³, exposure chamber was used to distribute an aerosol with a particle size of 2.68 μm, infected with motile and isogenically mutated nonmotile <i>Pseudomonas fragi</i> TM 849 in concentrations of 10² or 10⁶ cells/mL. Fifteen and 30 minute aerosol exposure times were used. Six pouches tested positive for test organism growth after a 72 hour incubation period. Pouch contamination via microbial ingress was significant (P < .05) for test organism motility (motile) and concentration (10⁶ cells/mL). / Master of Science