Abstract: Three kinds of atmosphere packaging(directly packaging,5% O2+10% CO2+85% N2 and 80% O2+20% N2)combined with three different densities of citric acid(0.5%,1% and 1.5%)were used to study the effect of the fresh-cut onion quality and safety during storage.The firmness,PPO activity and total bacteria count were determined during storage to evaluate the effect of different storage/processing methods.The results indicated that the package of 80% O2+20% N2 combined with 1.5% citric acid has the best effect.It can keep a good quality after 17 days storage under 4 ℃.

Key words: onion, high oxygen atmosphere packaging, PPO, firmness, total bacteria count (TBC), quality