: Microbiological analysis results (log CFU/g), pH, and TVB-N (mg N/100) in hamburgers of the different lots. The results of the microbiological analyses and the pH determination of the different batches are shown Table 1.The inoculation level of LAB (lot 2, 3 and 4) was at T0 between 4.82 and 5.01 log CFU/g. These level rapidly increased, regardless of the presence of 70% O2 in the MAP, reaching after 6 days loads between 6.16 and 7.65 Log CFU/g and after 9 and 12 days respectively loads between 7.68 and 8.88 Log CFU/g and loads between 8.05 and 8.90 Log CFU/g, respectively.Considering the control lot 1, the initial LAB was almost 4 log CFU/g, in agreement with those obtained by previous authors(Paleari et al., 2004). However, the concentration of LAB increased.