Effect of high oxygen modified atmosphere packaging on microbial growth and sensorial qualities of fresh-cut produce

Abstract

The application of High Oxygen Atmospheres (HOA) (i.e. >70% O 2) for packaging ready-to-eat vegetables was evaluated as an alternative technique for low O 2 Equilibrium Modified Atmosphere (EMA) packaging (3% O 2–5% CO 2–balance N 2) for respiring products. Comparative experiments between both techniques were performed in-vitro and in-vivo. Typical spoilage causing microorganisms ( Pseudomonas fluorescens, Candida lambica), the moulds Botrytis cinerea, Aspergillus flavus and the opportunistic psychrotrophic human pathogenic microorganism associated with refrigerated minimally processed vegetables, Aeromonas caviae (HG4), showed a retarded growth during the conducted in-vitro studies at 4 °C in 70%, 80% and 95% O 2 as examples of HOA compared to the in-vitro experiments in 5% O 2 (as example of EMA packaging) and the effect was more pronounced in 95% O 2. The effect of the high O 2-concentrations on the human pathogen Listeria monocytogenes resulted in an extended lag phase (95% O 2). The plant pathogen Erwinia carotovora was increasingly stimulated by increasing high O 2-concentrations. During a storage experiment of three types of ready-to-eat vegetables (mushroom slices, grated celeriac and shredded chicory endive), which are sensitive to enzymatic browning and microbial spoilage, the effect of EMA and HOA (95% O 2–5% N 2) on their quality and shelf life was compared. High O 2 atmospheres were found to be particularly effective in inhibiting enzymatic browning of the tested vegetables. Also, the microbial quality was better as a reduction in yeast growth was observed. The HOA can be applied as an alternative for low O 2 modified atmospheres for some specific types of ready-to-eat vegetables, sensitive to enzymatic browning and spoilage by yeasts.