Microbial and quality changes in minimally processed baby spinach leaves stored under super atmospheric oxygen and modified atmosphere conditions

The effect of super atmospheric O-2 and modified atmosphere packaging (MAP) on plant metabolism, organoleptic quality and microbial growth of minimally processed baby spinach was studied. Packaging film O-2 transmission rates and initial levels of super atmospheric O-2 in the packages significantly affected the changes of in-package atmospheres during storage, and consequently quality of baby spinach leaves. In general, a barrier film maintained a higher O-2 level for both 80 and 100 kPa O-2 treatments during entire storage. Packages with the barrier film also exhibited a more rapid accumulation of CO2 than those with the permeable film, with CO2 levels ranging from 16.2 to 22.5 kPa in the barrier film packages, versus 6.1-10.6 kPa in the permeable film packages at the end of 12 days of storage at 5 degreesC. Packages prepared with the barrier film with an initial O-2 level at 21% accumulated CO2 during storage and exhibited a significant reduction in aerobic mesophilic bacterial growth compared to the perforated film packages (control). However, this treatment also developed strong off-odor and a loss of tissue integrity. Adding super atmospheric O-2 to the packages alleviated tissue injury in addition to reducing microbial growth and was beneficial in maintaining quality of fresh-cut baby spinach. Published by Elsevier B.V.