High oxygen atmospheres can induce russet spotting development in minimally processed iceberg lettuce

• High O2 atmospheres reduced browning.
• High O2 atmospheres lead to accumulation of ethylene in the headspace.
• High O2 atmospheres induced development of russet spotting in fresh-cut lettuce.
• Russet spotting was not consistently prevented using ethylene absorbers.

High oxygen modified atmospheres have been suggested as an alternative preservation technique to classical low O2 modified atmosphere packaging (MAP) for fresh-cut lettuce. The advantages of high O2 storage would be a strong reduction of browning, avoidance of low O2 levels linked to off-odors, and the inhibition of microbial growth. However, storage under high O2 potentially could increase both production of ethylene and sensitivity to this hormone in lettuce tissue, leading to the development of quality problems linked to ethylene. In this study, different quality parameters (sensory quality, microbiological load, electrolyte leakage, volatile metabolites) were studied on fresh-cut iceberg lettuce stored under different gas conditions at 7 °C: (low O2 MAP (3% O2 compensated with N2), atmospheric conditions, high O2 MAP (50 or 90% O2 compensated with N2)). Furthermore, additional experiments using ethylene absorbers were performed in order to assess the link between high O2 storage, ethylene accumulation, and russet spotting. There was no significant difference between storage conditions regarding growth of mesophilic bacteria and yeasts, electrolyte leakage, or ethanol production. On the other hand, high O2 atmospheres reduced browning but promoted russet spotting development compared with low O2 and atmospheric conditions. In further specific experiments the relationship between high O2 storage, ethylene production, and russet spotting in fresh-cut iceberg lettuce were made evident.