  The influence of relative humidity (RH) on quasistatic current-voltage
${(I-V)}$ characteristics of Bifidobacterium animalis subsp. lactis BB-12 thin
layers have been studied for the first time. The value of electrical
conductivity in 75$ \%$ RH was found to be in the order of 10$^{-7}$ (ohm
cm)$^{-1}$ which was 10$^{6}$ orders of magnitude higher than that observed in
dry atmosphere. Here we also demonstrated that RH played a key role in
hysteresis behaviour of the measured ${(I-V)}$ characteristics. FTIR
measurements showed that under water moisture environment the associated bonds
for amine and carboxyl group were greatly strengthened that was the source of
number of free charge carries after ionization. The type of surface charge of
Bifidobacterium animalis subsp. lactis BB-12 was found to be negative by zeta
potential measurements, claiming that electrons were the charge carriers.
