The mean counts obtained for bifidobacteria with different culture media and incubation times are shown in Table 3. Only the counts of bifidobacteria obtained from FM 04 in Petrifim AC associated with RP-MUP after 24 h of incubation were significantly lower than the others (p < 0.01). Counts of bifidobacteria obtained in other media and at different incubation times showed no sig- nificant differences (p > 0.05). These results indicate that the pro- posed alternative protocols for the enumeration of bifidobacteria in fermented milk (RP-MUP and RP-MUP associated with Petrifilm AC plates with incubation for 24, 48 and 72 h) showed no signifi- cant differences when compared to the results obtained by following the ISO 29981 protocol, which uses TOS-MUP.
The equivalence between counts on TOS-MUP and RP-MUP can be confirmed by the distribution of the data presented in Fig. 1. The correlation parameters presented indicate the equivalence of these culture media for the enumeration of bifidobacteria in fermented milk.