Modified atmosphere packaging of shredded lettuce

Abstract

SummaryA retail package system was used to study the atmosphere modification which developed within packages of shredded Iceberg lettuce, sealed in trays with a range of polymer films of different gas permeabilities (oxygen permeability of 3000 to 10,000 ml/m2/day/atm. at 25°C). Modified atmospheres were produced both naturally by respiration, and by application of gas flushing techniques.The effects of these modified atmosphere conditions on visual and sensory quality of shredded lettuce was observed by monitoring colour change and development of off‐odours. An equilibrated modified atmosphere containing 1–3% O2 and 5–6% CO2was established with 35 um low density polyethylene film after flushing with 5% O2, 5% CO2 in N2. This resulted in a shelf‐life of approximately 14 days at 5°C, almost double that of the controls.