Physiological and microbiological changes in fresh-cut pears stored in high oxygen active packages compared with low oxygen active and passive modified atmosphere packaging

The application of high O2 atmospheres (HOA) of 70 kPa O2, balance N2, for active modified packaging of fresh-cut 'Flor de Invierno' pears was evaluated as an alternative to conventional low O2 atmosphere (LOA) active modified packaging (2.5 kPa O2 + 7 kPa CO2, balance N2), and to traditional passive atmosphere (PA) packaging. Gas exchange, color, firmness and microbiological stability were assessed throughout 28 days storage at 4 °C. HOA did not prevent the production of acetaldehyde and ethanol during storage of fresh-cut pears but their accumulation was promoted under anoxic conditions. Although LOA reduced CO2 production and inhibited ethylene production, moderate CO2 concentrations in combination with excessively low O2 levels inside packages accelerated the accumulation of fermentative metabolites. Both LOA and HOA significantly reduced the growth of microorganisms during storage. In addition, HOA had an inhibitory effect on some spoilage microorganisms such as Rhodotorula mucilaginosa isolated from fresh-cut 'Flor de Invierno' pears. Microbiological stability of fresh-cut pears stored under HOA was assured throughout storage, but commercial shelf-life may be limited by the browning appearance of the cut surfaces and off-odors beyond 14 days storage.