Remediation of soil contaminated by Salmonella enterica to expedite plant or replant of vegetables
Year: 2017
Type: dissertation
Abstract: Salmonella enterica is an important bacterial pathogen causing disease outbreaks associated with fresh produce. Improperly composted animal manure is a common environmental source of many enteropathogens in Australia. This study investigated methods for remediating Salmonella-contaminated soil by assessing the effect of environmental factors and soil type on the survival of Salmonella. Four Salmonella serovars were incubated at three temperatures (5, 21 and 37°C) under two moisture regimes (constant and fluctuating) and using two soil types (clay loam and coarse sand) with or without chicken manure in a microcosm pot trial. The survival of Salmonella was low under the following environmental conditions: coarse sand, high temperature, fluctuating moisture regimes, absence of manure. In the field study, soil deliberately inoculated with Salmonella was treated with soil solarisation and three low-residue cover crops to test potential remediation methods. In clay loam, Salmonella declined to below the quantitative limit of detection (LOD) in the control treatment after 105 days indicating natural die off of the pathogen. In coarse sand, Salmonella counts were below the LOD 14 days after inoculation. There was no difference among either cover crop alone or cover crop-solarisation treatments in hastening the decline of Salmonella. However, solarisation alone influenced the decline of Salmonella so it was below the LOD after 56 days. Information from microcosm pot trials and the field study indicated that an exclusion period of more than 90 days between application of untreated manure and crop harvest is required for clay soil. It was concluded that black plastic can be used as a solarisation treatment to remediate Salmonella-contaminated soil and that further research is warranted to exploit the potential of cover crops for their biocidal activity in suppressing Salmonella in the field.
Author: Mulatua Metaferia
Institution: The University of Sydney
Language: English
Subfield: Food Science
Domain: Life Sciences
Open Access status: green
Funder: University of California, Davis
OpenAlex ID: W2608682085