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Pathogen Reduction: Time, Temperature, and Beyond

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6th National Cultivating Community Composting Forum
Panel 5: BMPs and Rodent Control
James McSweeney
Compost Technical Services

Published in: Environment
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Pathogen Reduction: Time, Temperature, and Beyond

  1. 1. Pathogen Reduction Time/Temperature and Beyond
  2. 2. Community Resources Organic Matter Nutrients Energy Healthy Soil Healthy Plants Waste Reduction An d Human Pathogens Odors Runoff Vectors Weeds Contaminatio n Plant Compost
  3. 3. TIME/TEMPERATURE RELATIONSHIP
  4. 4. Regulations in US and Canada all have some version of: All compost particles must reach 131° F (55 C) or greater for at least 3 day. For turned piles the typical requirement is at least five turnings.
  5. 5. Pathogen Reduction Mechanisms • Thermal destruction • Production of toxic byproducts such as gaseous ammonia • Competition between indigenous microorganisms and pathogens • Antagonistic relationships between organisms • Antibiotics produced by certain fungi and actinomycetes • natural die-off in the compost environment (which is non-ideal for enteric (gut) pathogens) • Nutrient depletion Kristine Wichuck and Dary Mccartney. A review of the effectiveness of current time-temperature regulations on pathogen inactivation during composting. (Journal of Environmental Engineering and Science · August 2007).
  6. 6. Time Reduces Incidence of Pathogens
  7. 7. Pathogen Reduction Mechanisms • Thermal destruction • Production of toxic byproducts such as gaseous ammonia • Competition between indigenous microorganisms and pathogens • Antagonistic relationships between organisms • Antibiotics produced by certain fungi and actinomycetes • natural die-off in the compost environment (which is non-ideal for enteric (gut) pathogens) • Nutrient depletion Kristine Wichuck and Dary Mccartney. A review of the effectiveness of current time-temperature regulations on pathogen inactivation during composting. (Journal of Environmental Engineering and Science · August 2007). Curing is Insurance Policy
  8. 8. Key Factors to Ensure Pathogen Inactivation • Institutionalize BMPs • Track batches • Consistent temperature monitoring (1’ and 3’, multiple points) • Adopt maturity standard • Prevent reintroduction of pathogens ( keep high and dry) • Maintain aerobicity (small pile sizes)

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