Initial experiments were performed on MRD to investigate the
ability of different energy dosages to inactivate microorganisms in
medium with good transparency (3¼ 0.74). The energy doses
selected were sufficient to achieve a level of microbial inactivation
of approximately 5 log10 cfu/ml, which is in line with the minimum
inactivation recommended by the Food and Drugs Administration
(FDA, 2001) in fruit juices. In a study carried out by Huffman et al.
(2000) water treated with pulsed light at 0.25 J/cm2 (flow rate
15.41 l/min) gave a reduction of >7.4 log10 cfu/ml for Klebsiella
terrigena after two pulses. These results show that transparency of
the media allowed successful microbial inactivation using this
technology.