Effect of duration and temperature of previous vacuum-packed storage on the microbiological quality of Belgian Blue meat packed in high-oxygen atmosphere

The aim of this experiment was to study the effect of duration and temperature of
previous vacuum-packed (VP) storage on the microbiological quality of Belgian Blue
(BB) beef packed in high-oxygen atmosphere. VP striploins from bulls (B) and cows
(C) were stored at −1 °C and +4 °C for up to 80 days. These meats were
subsequently repackaged under modified atmosphere (MA) – 70 % O2/30 % CO2 – at
different times, and stored 2 d at +4 °C and 5 d at +8 °C. The average initial counts in
VP meats were 3.6 log CFU/cm² (B) and 2.7 log CFU/cm² (C) for total viable count
(TVC) at +22 °C; < 2.0 log CFU/cm² (B and C) for lactic ac id bacteria (LAB) at
+22 °C; 1.1 log CFU/cm² (B) and 1.3 log CFU/cm² (C) for Enterobacteriaceae at
+30 °C and < 1.0 log CFU/cm² (B and C) for Pseudomonas spp. and Brochothrix
thermosphacta. During the first 40 days of VP storage, temperature had a striking
influence on microbial growth. The maximum count differences between storage
temperatures were obtained at the 20th day of storage: 2.7 log CFU/cm² (B) and
2.9 log CFU/cm² (C) for TVC, 4.0 log CFU/cm² (B and C) for LAB and 3.6 log
CFU/cm² (B and C) for Enterobacteriaceae. The difference in TVC between
temperatures at the 20th day tended to disappear once the meats were repacked
under MA and stored during seven days. Conversely, the difference in LAB and
Enterobacteriaceae counts tended to be maintained after MA repackaging, showing
that duration and temperature of VP storage had influence on microbiological quality
of BB meat subsequently stored in high-oxygen atmosphere. Moreover, chilling at
temperatures very close to the freezing point of meat during VP storage, which has
already showed innumerous advantages for physicochemical quality of meat, was
capital to maintain the microbiological quality of BB fresh meat during subsequent
MA-packed storage.