The incubation temperature was also
responsible for the inhibition of L. acidophilus in M17 agar at 30 C
from cheeses (Table 4), since this microorganism has the optimum
growth temperature between 35 and 40 C (Hammes & Hertel,
2006; IDF, 1995). The selectivity of the M17 agar is also related to
the inhibitory effect of sodium glycerophosphate on different lactobacilli
strains (Shankar & Davies, 1977). This inhibitory effect was
confirmed by the lower counts of pure cultures of L. acidophilus in
M17 incubated at 37 C (Table 4) or 45 C (Table 3), and L. bulgaricus
in M17 incubated at 45 C (Table 3).