By: Wayne Du, On-Farm Food Safety Specialist

Do you use soil amendments such as manure or composted manure? Are you aware of the food safety risks? Here are some helpful tips to protect your crop from potential contamination.

What is the difference between manure and composted manure?

• Manure is raw or untreated animal excrement with or without bedding.
• Composted manure is the manure that has been treated or processed to eliminate or reduce harmful bacteria.

Tips for Using Composted Manure:

• Ensure manure is composted following proper compost procedures to ensure pathogens are reduced to an acceptable level. Factors affecting proper compost:
  • Temperature – general rule: 55 ^o C for 3 days/turning interval for 15 days.
  • Carbon Nitrogen ratio – ideal C:N ratio of 25:1 or 30:1.
  • Aeration – accomplished by frequent turning of the pile.
  • Moisture– ideal 50-60% water by weight.
  • Clean and sanitize any equipment used to handle raw manure before handling finished compost and between uses.
  • If purchasing composted manure, request a certificate of analysis or documentation of treatment method from the supplier to ensure the composting process has been completed.

Tips for Using Manure:

• When possible, avoid using manure which poses a greater risk for microbial contamination than composted manure.
• Incorporate manure into the soil within 24 hours after application to minimize contamination to adjacent crops from wind drift or runoff.
• Establish 5-10 metre vegetated areas along water ways to reduce the potential for pathogens entering surface water.
• Do not apply manure on frozen soil or when it is raining.
• Take precautions when using manure to fertilize produce crops that can be consumed raw:
  • Ensure a minimum of 4 months between manure application and harvest.
  • Ensure manure does not come into contact with the edible part of the crop.
  • Apply manure post-harvest.
  • Apply manure in non-fruiting years.

For more information on manure and composting, proper handling and application and storage requirements, refer to the Ontario Nutrient Management Act and OMAF/MRA’s Factsheets on manure composting.

Food safety is everyone’s responsibility. To attend our free online workshops on manure use and other important food safety topics, visit us at: www.ontario.ca/foodsafety or call: 1-877-424-1300. Food safety practices keep agri-food businesses competitive, productive and sustainable.