Effect of superatmospheric oxygen packaging on sensorial quality, spoilage, and Listeria monocytogenes and Aeromonas caviae growth in fresh processed mixed salads.
Allende, A., Jacxsens, L., Devlieghere, F., Debevere, J. and Artes, F.
Journal of Food Protection. Volume 65, Number 10, 2002. Pages 1565-1573 .
2002
บทคัดย่อ
Atmospheres with O2 levels higher than 70 kPa have recently been suggested as an innovation to modified atmosphere packaging (MAP) for fresh processed vegetables to maintain sensory quality and safety. In the present work, mixed vegetable salad collected from a commercial processing plant and stored with the MAP technique was studied. Two gas mixtures were actively generated by using an initial O2 concentration of 95 kPa and combined with 2 plastic films. The low-barrier film permeability for O2 was 1629 ml O2/m2 x 24 h x atm with 30 micro m of thickness (Hyplast, Hoogstraten, Belgium) and the O2 permeability of the high-barrier film was 2 ml O2/m2 x 24 h x atm with 150 micro m of thickness (Euralpack, Wommelgen, Belgium) at 23 deg C. As control, active conventional MAP with application of 3 to 5 kPa of O2 and 6 to 8 kPa of CO2 was used. Packaged salads were stored up to 8 days at 4 deg C and at temperatures simulating chilled distribution chain conditions. Microbial safety and sensory quality, as well as the survival of inoculated Listeria monocytogenes and Aeromonas caviae, were monitored. The effect of superatmospheric O2 on the growth of aerobic microflora was variable. Under superatmospheric conditions, lactic acid bacteria and members of Enterobacteriaceae were inhibited. Nevertheless, growth of yeast and A. caviae seem to be stimulated by superatmospheric O2, whereas growth of psychrotrophic bacteria and L. monocytogenes was not affected. The overall visual appearance (mainly colour) of the mixed vegetable salads was better maintained and the shelf life prolonged when packaged under O2 concentrations greater than 50 kPa.