Before inoculating
with the WRF, the moisture content of OPF was adjusted to 670 g/kg by adding 45 ml of distilled water to 45 g OPF directly in
each inoculation recipient. To assure absence of active microorganisms, the OPF were autoclaved twice at 121 ◦C for 20 min
with cooling between cycles. After cooling, 45 ml of buffer solution was added to each recipient with OPF in order to maintain
the pH at 5.5.