The particular strain of E. coli was the Food Drug Administration “Seattle Strain” Escherichia coli American
Type Culture Collection 25922. The Food Research Group at the University of Adelaide provided the sample.
Luria Broth Lennox (LB) 1.5%w/v was used as a liquid growth medium for all cultures. The E. coli strain was
cultured before each test from a suspended refrigerated stock culture. Aseptic technique [40] was used to inoculate a
single colony of the culture into a 30 mL test tube of LB, and the tube was incubated for eight hours at 37oC.
Following incubation, 1 mL of the inoculum was pipetted into a 50 mL flask of LB and sealed with sterile cotton
bung. This larger volume was then incubated for 16 hours overnight in a rotator shaker incubator to induce an
aerobic growth environment. This ensured maximum growth of harvested cells with a uniform resistance to UV
radiation. Bacterial cells were harvested from the growth media through centrifugation to minimize stress to the
bacteria and increase chance of survival. Counts were consistently in the order of 1010 per mL.
Water samples of 2 mL were taken at regular intervals throughout the test from a specially installed septum in the
centre of the reactor tube. Standard plating technique [40] was applied for each 2mL sample, with a 6-log dilution