Use of zero-valent iron biosand filters to reduce Escherichia coli O157:H12 in irrigation water applied to spinach plants in a field setting

What is it about?

Zero-valent iron may provide a cost effective mechanism to reduce the dissemination of foodborne pathogens introduced to produce in contaminated water. These experiments are the first to evaluate a zerovalent iron irrigation water decontamination on field scale. Spinach was planted, and biosand filters containing sand (S), sand and zerovalent iron (SI), or control filters were built at the field site. E coli O157:H12 was introduced to into ground water and filtered through three fiters. On day 0, right after inoculation of water and the filtering of water, SI columns were significantly more effective at killing and removing high numbers of E. coli from irrigation water. Spinach plants were also irrigated with contaminated water and filtered with either S or SI columns. Spinach irrigated with SI-filtered water had ca.4-5 log decrease when compared to plants irrigated with either the control or the S-filtered column. Overall, our results show that aero-valent iron can be effective in reducing the dissemination of foodborne illness attributed to produce, and provide a simple and relatively cost-effective method for smaller growers and farmers.

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