Inactivation of Cryptosporidium parvum oocysts and faecal indicator bacteria in cattle slurry by addition of ammonia

H. H. Petersen*, A. Dalsgaard, B. Vinneras, L. S. Jensen, T. T.A. Le, M. A. Petersen, H. L. Enemark, A. Forslund

*Corresponding author for this work
4 Citations (Scopus)

Abstract

Aims: To determine inactivation of Cryptosporidium parvum oocysts and reduction of Escherichia coli and enterococci in cattle slurry added aqueous ammonia. Methods and Results: Escherichia coli, enterococci and nonviable C. parvum oocysts (DAPI+PI+) were enumerated every second day for 2 weeks in cattle slurry amended with 60 mmol l−1 aq. ammonia and compared with untreated slurry at three temperatures. Regardless of temperature, the proportion of nonviable C. parvum oocysts increased significantly faster over time in slurry with added ammonia than raw slurry (P = 0·021) corresponding to 62·0% higher inactivation (P = 0·001) at day 14. Additionally, 91·8% fewer E. coli and 27·3% fewer enterococci were observed in slurry added ammonia at day 14 compared to raw slurry. Conclusion: The addition of aqueous ammonia to raw slurry significantly reduced the viability of C. parvum oocysts and numbers of bacterial indicators. Hence, ammonia is usable at lower pathogen concentrations in slurry before application to agricultural land. Significance and Impact of the Study: Livestock waste is a valuable source of plant nutrients and organic matter, but may contain high concentrations of pathogens like E. coli and Cryptosporidium sp. that can be spread in the environment, and cause disease outbreaks. However, die-off rates of pathogens in organic waste can increase following increasing ammonia concentrations.

Original languageEnglish
JournalJournal of Applied Microbiology
Volume130
Issue number5
Pages (from-to)1745-1757
Number of pages13
ISSN1364-5072
DOIs
Publication statusPublished - May 2021

Keywords

  • ammonia
  • cattle slurry
  • Cryptosporidium parvum
  • enterococci
  • Escherichia coli
  • faecal indicator bacteria

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