Abstract: In order to investigate the effect of different packaging methods on meat quality, microbial counts and microbial community succession in beef steaks during storage, meat samples were stored in modified atmosphere (50% O2 + 30% CO2 + 20% N2) or vacuum at 0-4 ℃ and evaluated for pH, meat color, microbial counts and bacterial diversity after 0, 3, 7, 14 and 21 days. The results showed that modified atmosphere packaging (MAP) maintained meat color better than vacuum packaging (VP). On day 21, the total viable count, lactic acid bacterial count and Pseudomonas spp. count in the MAP group decreased as compared to those in the VP group. The microbial diversity in both groups increased at first and then decreased as storage time was extended, being more complex in the VP group than in the MAP group. The initial bacterial community in steaks was dominated by Acinetobacter, Ochrobactrum, Thermus and Chryseobacterium, and then Carnobacterium gradually became the dominant microorganism in the VP group, while Brochothrix, Serratia and Lactobacillus eventually became the dominant microorganisms in the MAP group. The storage time from day 7 to 14 was the critical period for the changes in microbial species in beef steaks. Higher protein and lower carbohydrate metabolism levels in the MAP group were found compared with the VP group. The results from this study may provide a reference for targeted inhibition of microorganisms in beef steaks and prolonging the shelf life.

Key words: beef steak, modified atmosphere packaging, vacuum packaging, microbial diversity, microbial community succession