  We have shown elsewhere that the presence of mixed-culture growth of
microbial species in fermentation processes can be detected with high accuracy
by employing the wavelet transform. This is achieved because the crosses in the
different growth processes contributing to the total biomass signal appear as
singularities that are very well evidenced through their singularity cones in
the wavelet transform. However, we used very simple two-species cases. In this
work, we extend the wavelet method to a more complicated illustrative
fermentation case of three microbial species for which we employ several
wavelets of different number of vanishing moments in order to eliminate
possible numerical artifacts. Working in this way allows to filter in a more
precise way the numerical values of the H\"older exponents. Therefore, we were
able to determine the characteristic H\"older exponents for the corresponding
crossing singularities of the microbial growth processes and their stability
logarithmic scale ranges up to the first decimal in the value of the
characteristic exponents. Since calibrating the mixed microbial growth by means
of their H\"older exponents could have potential industrial applications, the
dependence of the H\"older exponents on the kinetic and physical parameters of
the growth models remains as a future experimental task
