The effectiveness of treating irrigation water using ultraviolet radiation or sulphuric acid fertilizer for reducing generic Escherichia coli on fresh produce-a controlled intervention trial.

W Beauvais, April Englishbey, C M Marconi, U Cholula, A M Belias, M Wemette, J Usaga, J J Churey, R W Worobo, J Enciso, J R Anciso, Kendra Nightingale, R Ivanek

Research output: Contribution to journalArticle

2 Scopus citations

Abstract

Aims: The aims of this study were to: (i) estimate the effectiveness of ultraviolet radiation (UV) and sulphuric acid-based fertilizer (SA), at reducing levels of generic Escherichia coli in surface irrigation water and on produce and surface soil in open produce fields; and (ii) describe the population dynamics of generic E. coli in produce fields. Methods and Results: Spinach and cantaloupe plots were randomly assigned to control, UV or SA treatment groups. Irrigation water was inoculated with Rifampicin-resistant E. coli prior to treatment. More than 75% of UV- and SA-treated tank water samples had counts below the detection limit, compared to a mean count of 3·3 Log10 CFU per ml before treatment. Levels of Rifampicin-resistant E. coli in soil and produce both increased and decreased over 10–15 days after irrigation, depending on the plot and time-period. Conclusions: UV and SA treatments effectively reduce the levels of E. coli in surface irrigation water. Their effectiveness at reducing contamination on produce was dependent on environmental conditions. Applying wait-times after irrigation and prior to harvest is not a reliable means of mitigating against contaminated produce. Significance and Impact of the Study: The results are of timely importance for the agricultural industry as new FSMA guidelines require producers to demonstrate a low microbial load in irrigation water or allow producers to apply a wait-time to mitigate the risk of contaminated produce.

Original languageEnglish
Pages (from-to)1360-1377
Number of pages18
JournalDefault journal
Volume131
Issue number3
DOIs
StatePublished - Sep 1 2021

Keywords

  • agriculture
  • food safety
  • microbial contamination
  • ultraviolet applications
  • water

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