Food Safety in Gardens

HYG-1153
Date: 
01/12/2017
Sanja Ilic, PhD, Assistant Professor and Food Safety State Specialist, Department of Human Sciences, Human Nutrition
Melanie Lewis Ivey, PhD, Assistant Professor, Fruit Pathologist, Department of Plant Pathology

Growing fruits and vegetables in a home, school or community garden has many healthful benefits. Gardening can reduce stress, improve mental clarity, increase physical activity and increase awareness of healthy nutrition. However, there are potential food safety challenges that should be addressed when growing fruits and vegetables.

From the garden to the kitchen, there are many opportunities for bacteria, viruses and parasites to contaminate your produce. Bacteria such as Salmonella, pathogenic E. coli and Listeria monocytogenes and viruses such as norovirus are commonly linked to contaminated fresh produce. These pathogens can be a problem whether you are using organic or conventional gardening methods. Dirty water, soil, soil amendments, animals, gardening tools and peoples’ hands are potential sources of these harmful bacteria and viruses. In addition, damaged or decaying produce provide conditions that can support the growth of human pathogens. Simple practices can be used in the garden to reduce the risks of produce contamination and prevent foodborne illnesses.

Practices that reduce the risk of contaminating fruits and vegetables in the garden

Garden Location

Food safety risks can be reduced by selecting a location for your garden that is not in close proximity to a sewage system, animal-based compost piles or farm animals (i.e., hen house). Locations that are susceptible to flooding or exposure to agricultural run-off water should be avoided. Planting on level ground to prevent standing water is recommended. Have your soil tested for nutrients (macro and micro), pH and heavy metals such as cadmium, mercury and copper. This information is useful for choosing the best location for growing crops and for determining the use of soil amendments. The fact sheet “Soil Testing for Ohio Lawns, Landscapes, Fruit Crops, and Vegetable Gardens” (HYG-1132) provides detailed information on soil tests, sampling and testing labs in the state.

Soil Amendments

Composted or aged (also called stabilized) manure, or other soil amendments containing any animal components, such as manure, meat, egg shells or bones, are not recommended for gardens as they may not be thoroughly processed and thus contain foodborne pathogens. Compost prepared from grass clippings or plant trimmings, provided the plants are not diseased or infested with pests, are good alternatives to animal-based composts. The fact sheet “Composting at Home” (COM-0001-99) provides detailed information on how to prepare safe compost for the garden. If you choose to use animal-based compost in your garden, it should be commercially processed and applied well before (at least 90 days) you begin to harvest your crops. Compost should be stored away and downhill from your garden and should be enclosed and covered to prevent animals from digging in it. When handling compost wear protective gloves. Cloth or leather gloves should be washed immediately after handling animal-based compost.

Water

Know the source and quality of your water. Water can be contaminated with foodborne pathogens and these pathogens can easily be transferred to produce through irrigation, fertilizing or flooding. Drip irrigation (also called trickle irrigation) or soaker hoses are the preferred method of irrigation. If wands are used, point the nozzle of the wand at the base of the plant. By minimizing direct water contact with the edible portions of your plants the risk of contamination with pathogens in the water is reduced.

City water, which is treated to meet state and federal drinking water standards (potable water), is recommended to irrigate, prepare fertilizer or pesticides, and wash your fruits and vegetables. If your water is from a well, ensure that the well is properly maintained and the water is tested on a regular basis. Refer to the fact sheet “Where to Have Your Water Tested” (AEX-315) for a list of water testing laboratories in Ohio. Well water must also meet drinking water standards. 

Collecting rainwater is a great way to conserve water but it can contain pathogens and harmful metals from the roof or gutters. Treating rainwater (e.g., filtration and chlorination) before applying it to the garden is recommended. Other water sources, such as surface water from rivers, ponds or ditches, are not recommended. Surface water can contain high levels of pathogens and should be avoided. 

Animals

Domestic pets, stray animals and wildlife droppings carry a number of foodborne pathogens and are a source of produce contamination. Although challenging, restricting animals like raccoons, rabbits, rodents, birds and chipmunks from entering the garden is recommended. Weeding the garden regularly and removing dead plants or fallen fruit will deter small animals from nesting or searching for food in the garden. Fences will keep large animals like deer away. Birds can be deterred with noisemakers or predator decoys. Stringing fishing line over the garden will also help to keep birds from landing in the garden.

Tool and Surface Sanitation

Pathogens can end up on fresh produce through cross-contamination from dirty surfaces. Harvesting tools such as clippers or scissors and containers used to hold produce (i.e., pails, bowls, colanders) should be cleaned and sanitized before each use. Plastic bags can be used to collect fruits and vegetables but should not be reused. Avoid placing harvested produce directly on the ground. Surfaces can be cleaned with soap and water and sanitized with a dilute solution of bleach (1 Tablespoon per gallon of water). Remember to always use potable water to wash surfaces or mix sanitizers.

Handwashing 

Handwashing is a simple and effective way to prevent foodborne illnesses. Wash your hands for at least 30 seconds with soap and potable water and dry them thoroughly with a disposable towel. Hand sanitizers can be used if soap and water are not readily available. However, hand sanitizers will not eliminate all types of pathogens present on your hands and are especially ineffective if your hands are visibly dirty. Always wash your hands before entering the garden or harvesting; after handling compost, plant debris or garbage; after touching a pet or farm animal; and after using the toilet.

Suggested Resources
Blogs, J., Meyer, C., Gao, G., and Chatfield, J. 2016. Soil testing for Ohio lawns, landscapes, fruit crops, and vegetable gardens. HYG-1132. Ohio State University Extension, Columbus, OH. ohioline.osu.edu/factsheet/hyg-1132
Mancl, K., and Sengupta, S. 2010. Where to have your water tested. AEX-315. Agriculture and Natural Resources, Ohio State University Extension, Columbus, OH. ohioline.osu.edu/factsheet/AEX-315
Michel, F.C., Heimlich, J.E., and Hoitink, H.A. 1999. Composting at home. COM-0001-99. Horticulture and Crop Sciences, Ohio State University Extension, Columbus, OH. (not currently available online)
 
References 
Chaifetz, A., Driscoll, E., Gunter, C., and Chapman, B. 2012. Food Safety in School and Community Gardens. A handbook for beginning and veteran garden organizers: Reducing food safety risks. Cooperative Extension, North Carolina State University, Raleigh, NC.
Scallan, E., et al. 2011. Foodborne illness acquired in the United States—major pathogens. Emerg. Infect. Dis. 17:1.
U.S. Food and Drug Administration. 2013. FDA Food Safety Modernization Act (FSMA). U.S. Department of Health and Human Services, www.fda.gov/Food/GuidanceRegulation/FSMA/default.htm (accessed July 1, 2016).
 
Topics: 
Ohioline http://ohioline.osu.edu