Effect of nitrogen gas packaging on the quality and microbial growth of fresh-cut vegetables under low temperatures

Nitrogen (N-2) gas packaging for fresh-cut vegetables (lettuce and cabbage) has been examined as a means of modified atmosphere packaging (MAP) for extending the shelf life of cut vegetables. Gas composition in enclosed packages that contained cut vegetables and were filled with 100% N-2 had an oxygen (O-2) concentration of 1.2 to 5.0% and a carbon dioxide (CO2) concentration of 0.5 to 3.5% after 5 days of storage. An atmosphere of low concentrations of O-2 and high CO2 conditions occurred naturally in the package filled with N-2 gas. Degradation of cut vegetables in terms of appearance was delayed by N-2 gas packaging. Because of this effect, the appearance of fresh-cut vegetables packaged with N-2 gas remained acceptable at temperatures below 5degreesC after 5 days. Treatment with acidic electrolyzed water (AcEW) contributed to the acceptability of the vegetables' appearance at 5 and 10degreesC in the air-packaging system. N-2 gas packaging did not significantly affect the growth of microbial populations (total aerobic bacteria, coliform. bacteria, Bacillus cereus, and psychrotrophic bacteria) in or on cut vegetables at 1, 5, and 10degreesC for 5 days. Microbial growth in or on the cut vegetables was inhibited at 1degreesC for 5 days regardless of atmospheric conditions.