A Bayesian inference approach to quantify average pathogen loads in farmyard manure and slurry using open-source
Rajat Nag1, Bryan K Markey2, Paul Whyte2
1University College Dublin, School of Biosystems and Food Engineering, Belfield, Dublin 4, Ireland.
The Science of the Total Environment
|May 9, 2021
Summary
This study estimates initial pathogen concentrations in animal waste using 14 years of data. Cryptosporidium spp. showed the highest prevalence in cattle, informing farm-to-fork risk assessments.
Area of Science:
- Food safety
- Microbial risk assessment
- Veterinary epidemiology
Background:
- Quantitative microbial risk assessments (QMRA) rely on accurate initial pathogen concentration estimates.
- Estimating initial pathogen loading in animal faeces is crucial for farm-to-fork QMRA.
- Data on pathogen prevalence and levels in livestock waste is essential for risk modeling.
Purpose of the Study:
- To collate and analyze 14 years of data on pathogen prevalence and initial concentrations in animal waste.
- To provide a robust basis for initial pathogen loading values in farm-to-fork QMRA models.
- To assess the prevalence of key pathogens like Cryptosporidium, MAP, Salmonella, Clostridium, Campylobacter, E. coli, and Listeria in cattle, pigs, and sheep.
Main Methods:
- Utilized a Bayesian inference loop to analyze 14 years of historical and current survey data.
- Collected and assessed data on pathogen prevalence (P) and initial concentration (C_initial) in animal faeces, manure, and slurry.
- Focused on pathogens including Cryptosporidium spp., Mycobacterium avium subspecies paratuberculosis (MAP), Salmonella spp., Clostridium spp., Campylobacter spp., pathogenic E. coli, and Listeria monocytogenes.
Main Results:
- Cryptosporidium spp. exhibited the highest mean prevalence (P_mean) in cattle (25.93%), followed by MAP (15.68%) and Campylobacter spp. (8.80%).
- Highest P_mean for E. coli was observed in pigs (7.42%), and for Clostridium spp. in sheep (7.94%).
- Derived average initial concentrations (C_initial) for various pathogens in cattle faeces, pig slurry, and sheep manure.
Conclusions:
- This study provides essential baseline data for initial pathogen loading in animal waste.
- The findings enhance the accuracy of farm-to-fork QMRA models by offering reliable pathogen concentration estimates.
- The research supports improved risk assessment strategies for food safety originating from livestock production.
