Abstract:

Modified atmosphere packaging (MAP) with helium (He) mixtures was evaluated for beneficial effect on the
quality of chilled pork with the aim of developing a way to prolong its shelf life. A total of 150 samples of chilled pork
weighing approximately 100 g each were randomly assigned to five groups with 30 samples in each group: Ⅰ, control;
Ⅱ, Ⅲ, Ⅳ and Ⅴ, MAP with 100% N2, 50% He plus 50% N2, 50% He plus 50% CO2 and 50% N2 plus 50% CO2,
respectively. All these samples were stored at 0 ℃ and microbial, physiochemical and sensory indicators were measured after
0, 5 12, 19 d and 26 d (0, 5 d and 12 d for group Ⅰ). The results showed that: 1) four different modified atmospheres presented
obvious inhibitory effect against microbial growth. The antimicrobial effect was stronger under MAP with CO2
mixtures (Ⅳ and Ⅴ). The best antimicrobial effect was found under MAP with He/CO2 mixtures (Ⅳ). 2) four MAP
treatments did not exhibit any additional effect on pH. 3) Compared with group Ⅰ stored for 5 d, no difference in TVB-N value,
putrescine and cadaverine contents or overall sensory evaluation scores of group Ⅱ and Ⅲ stored for 12 d, group Ⅴ
stored for 19 d and group Ⅳ stored for 26 d were observed (P ＞ 0.05). All the MAP treatments appeared to have
protective effect on the color of chilled pork. The shelf life of chilled pork was prolonged for 1 week in groups Ⅱ and
Ⅲ, 2 weeks in group Ⅴ and 3 weeks in group Ⅳ when compared with group Ⅰ. The MAP with He/CO2 mixture was
the most effective in preserving chilled pork.

Key words: helium, modified-atmosphere packaging, chilled pork, shelf life, microorganism, sensory quality