Abstract:

Longissimus dorsi muscles (n = 6) from Chinese yellow cattle were irradiated at doses of 1.241, 2.300 and 3.429 kGy
using a high-energy electronic irradiation accelerator and then stored at 4 ℃ in a nitrogen atmosphere. The changes in
microbial, biochemical and sensory characteristic of chilled beef during each storage period were monitored. Compared
with the control group, total bacterial counts of three treated groups declined significantly (P < 0.05). At 0 day of storage,
total bacterial counts of the low-, middle- and high-dose groups decreased by 0.766, 1.801 and 2.673 (lg(CFU/g)) compared
with the control group. The effects of electron beam irradiation on purge loss, surface color, pH value and thiobarbituric
acid reactive substances (TBARS) value of chilled beef were not significant. In addition, there was a small difference in
total volatile basic nitrogen (TVB-N) values between the control and tested groups. However, sensory scores for color, odor
and acceptability declined with irradiation dose. Comprehensive analysis of various quality indicators revealed that electron
beam irradiation at low dose of 2.5 kGy improved the microbiological quality and extended the shelf-life of chilled beef
packaged in modified atmosphere.

Key words: electron beam irradiation, chilled beef, modified atmosphere, microbiology, biochemistry, sensory characteristics