Food Safety: Growing safe, wholesome produce in home gardens

It is time to start planting summer gardens and thinking about the upcoming harvest. A lot of effort typically goes into gardening, so ensure your produce is safe to eat and your gardening season successful by following these tips.

Siting your garden

Make sure to choose a garden location free of contaminants, away from sewage drain fields, well caps, garbage cans, manure or compost piles and areas frequented by animals. It is important to remember that wind and runoff can transport contaminants and harmful microorganisms into your garden, so choose a location that minimizes these hazards. Prevent food safety issues by considering the soil, water and surrounding environment.

Soil amendments

Manure, compost and other soil amendments can increase soil health and improve the growth of plants but may also carry pathogens that can spread to fresh produce. It is best to use soil amendments that have been treated to kill pathogens, but if untreated soil amendments are used, they should be applied in late fall after the last harvest. If untreated soil amendments are used at the start of the growing season, preferably apply them before planting and before any harvestable portion of the crop is available. Never add soil amendments when plants are blooming or when the harvestable portion of the crop is present. Always store soil amendments away from your garden so wind and runoff don’t carry them into your garden.

Water sources

Some irrigation sources are at higher risk of harboring pathogens than others. Municipal water has been treated and is the safest option for watering your garden. Groundwater from private wells is an unlikely source of contamination, but the water should be tested annually to ensure it is safe to use in your garden and home. Many people like to capture and use rainwater as a source of irrigation. However, surface water, including captured rainwater, ponds, creeks, and other sources exposed to the environment, pose the highest risk for containing pathogens and chemical contaminants. If surface water is used for watering — despite the risks — drip irrigation is generally safer than overhead.

Drip irrigation water is less likely to contact the harvestable portion of the crop.

Additionally, drip irrigation reduces water use since it is applied directly to the soil.

Keeping animals away

Many pathogens are spread through animal feces, so it is essential to keep animals out of your garden. Cat feces can carry Toxoplasma gondii, a parasite that causes the disease toxoplasmosis. Pregnant women who consume produce contaminated with T. gondii can pass this infection to their unborn baby. Toxoplasmosis, the disease caused by T. gondii, can result in miscarriage or stillbirth for pregnant women, or vision loss, mental disability, and seizures in infants. Birds, including backyard chickens, can spread Salmonella to fresh produce, while deer, cattle, goats, sheep, and other animals can spread diseases like E. coli. It is best to use fencing around your garden to keep wildlife and domesticated animals out, but other deterrents include reflective tape, decoys, and netting.

Harvesting produce

Wash your hands with soap and water for at least 20 seconds before touching any produce. If you wear gloves, make sure the gloves are clean and in good condition. Tools and food-grade containers should be cleaned with soap and water before harvesting produce. Do not use containers that previously contained nonfood items or chemicals. Never harvest produce that has come into contact with feces. The surface of fresh produce is excellent at trapping pathogens, so once produce is contaminated, it is nearly impossible to completely remove the pathogens.

Produce should only be washed using potable, running water. Although there are produce washes on the market, they have not been deemed effective for cleaning produce and may even add contaminants during washing. A clean vegetable brush may be used on thick-skinned produce to help scrub away soil and other contaminants.

By following these gardening tips, you can improve the safety of this season’s fresh produce: Happy gardening.

Smith is an assistant professor and statewide consumer food specialist for Washington State University. She can be reached at food.safety@wsu.edu. If you have a food safety question you would like to see in this column, send your question to us at food.safety@wsu.edu.