Cereal grains can contain high bacterial loads so that a microbial reduction step is desired. Therefore, a
low pressure circulating fluidized bed reactor for the treatment of granular materials was constructed,
and an argon/oxygen plasma was ignited in the riser tube by an inductively coupled RF-source. With this
setup, the viability of Bacillus amyloliquefaciens endospores, artificially deposited on wheat grains, could
be reduced by over two logarithmic units within 30 s of effective treatment time. In addition, the
influence of plasma power input and variation in oxygen gas admixture was studied. Based on energy
influx measurements and the solution of the heat equation, a thermal inactivation effect and the thermal
degradation of wheat grains could be excluded. No negative effects of plasma treatment on wheat grain
properties were detected in flour and dough analyses.