The document discusses pathogen reduction during the composting process. It outlines regulations in the US and Canada that require compost particles to reach 131°F for at least 3 days. It also lists the various mechanisms by which pathogens can be reduced during composting, including thermal destruction, production of toxic byproducts, competition from other microorganisms, and nutrient depletion. The document emphasizes that consistent temperature monitoring and following best practices are key to ensuring pathogen inactivation.

1. Pathogen
Reduction
Time/Temperature
and
Beyond

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. TIME/TEMPERATURE
RELATIONSHIP

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. 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. Time Reduces Incidence of Pathogens

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. 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)