For an avid gardener, there's no such thing as waste. Almost any form of natural material deserves consideration for the compost pile. Manure is an obvious candidate, given its traditional value as a fertilizer. Sheep, horse and cattle manure are widely available for purchase or barter. Manure from wild animals such as deer can also be used, though there are some potential risks to be aware of.
E. coli and Other Risks
The U.S. Department of Agriculture's Natural Resources Conservation Service considers deer manure, like the droppings of other ruminants, to be a risk factor for the spread of the dangerous O157:H7 strain of Escherichia coli (see Reference 1, page 4). These bacteria can cause serious illness even in healthy adults and can be life-threatening in children, seniors and anyone with a compromised immune system (see Reference 2). The U.S. Food and Drug Administration considers manure to be at least a potential source of other dangerous bacteria, including Listeria monocytogenes and Salmonella (see Reference 3).
Composting and Bacteria
If it's properly managed, your compost can generate a high enough temperature to kill any potentially harmful bacteria in deer manure. A study published in 2011 in the journal "Applied and Environmental Microbiology" evaluated survival rates for E. coli in compost at varying temperatures (see Reference 4). The bacteria showed an ability to survive for several days at temperatures between 50 and 70 C, or approximately 120 and 160 F. At least one week of high temperatures is necessary to kill the bacteria, and two weeks is preferable for added safety.
Using the Compost
Maintaining your compost pile at high temperatures for extended periods requires both experience and suitable equipment, such as a long compost thermometer. The resulting compost is safe to use even on your vegetable garden, though you should still be scrupulous about washing your fresh produce before peeling it or eating it raw. If you have any qualms, compost deer manure separately and use the fertilizer for flower beds, trees and other areas from which you won't eat the plants you grow.
You're not the only one who might put deer manure in your garden. Deer scatter their droppings in random places around your yard and garden, and despite your best efforts, your vegetables might become contaminated with E. coli or other bacteria. You can reduce the risk by collecting deer droppings whenever you find them. Root vegetables and leafy greens are the highest-risk vegetables for bacterial contamination (see Reference 3), so be careful when you handle them. The USDA's Food Safety and Inspection Service recommends careful washing in cold water, as well as scrubbing with a soft brush when appropriate (see Reference 5).
- USDA National Resources Conservation Service: Reducing Risk of E. coli O157:H7 Contamination
- Centers for Disease Control and Prevention: Escherichia coli O157:H7 and Other Shiga Toxin-Producing Escherichia coli (STEC)
- U.S. Food and Drug Administration: Production Practices as Risk Factors in Microbial Food Safety of Fresh and Fresh-Cut Produce
- Applied and Environmental Microbiology; Determining Thermal Inactivation of Escherichia coli O157:H7 in Fresh Compost by Simulating Early Phases of the Composting Process; Randhir Singh et al.
- USDA Food Safety and Inspection Service: Washing Food -- Does It Promote Food Safety?
Fred Decker is a trained chef and certified food-safety trainer. Decker wrote for the Saint John, New Brunswick Telegraph-Journal, and has been published in Canada's Hospitality and Foodservice magazine. He's held positions selling computers, insurance and mutual funds, and was educated at Memorial University of Newfoundland and the Northern Alberta Institute of Technology.