Fate and survival of Salmonella Typhimurium and Escherichia coli O157:H7 in repacked soil lysimeters after application of cattle slurry and human urine.

ABSTRACT

BACKGROUND: Use of cattle slurry as a fertiliser is common practice around the world. Human urine use is not as common, but owing to its fertiliser value this might change in the future. It is essential to minimise the transfer of enteric pathogens through fertilisation, with respect to both animal and public health. Therefore the objective of this research was to study the survival and transport of Salmonella Typhimurium and Escherichia coli O157H7 in two agricultural soils when applied to soil along with either cattle slurry or human urine over a period of 180 days. RESULTS: Both Salmonella and E. coli O157H7 were more rapidly reduced when applied together with human urine than when applied with cattle slurry. However, both pathogens persisted in low amounts at 20 and 50 cm depth in both soils throughout the whole study period. No Salmonella or E. coli O157H7 was detected in the leachate over the 180 day study. CONCLUSION: The risk of disease transmission is higher when cattle slurry is used as fertiliser compared with human urine. However, the risk of groundwater infiltration would be low as long as water velocity through the soil is moderate. Increased knowledge of pathogen persistence in soil after fertiliser application is a valuable tool for improving risk evaluations and formulating guidelines for the use of cattle and/or human wastes in cropping soils.