Grow Smart: Keep Food Safe

When you grow your own food, you can take steps to prevent food-borne illness from creeping into your crops. Here’s how.

by Sharon Biggs Waller
Lettuce rows
Courtesy Polka Dot/
By growing your own fruits and vegetables, you have better control over your food safety.

When it comes to food safety in growing fruits and vegetables, it doesn’t matter if you’re a commercial wholesale grower, hobby farmer, home gardener or direct marketer, the risk of food-borne illness is the same and the precautions that need to be taken are very similar, says Roy Ballard, Purdue Extension educator for agriculture and natural resources in Greenfield, Ind. Good agricultural practices should be implemented by every farmer, no matter the size of the garden or field.

“Most home gardeners are very cavalier about food-borne illness in the garden,” Ballard says. “People eat veggies right out of the field or rub off a tomato with a bird dropping on it and then eat it. Sometimes a gardener may side-dress crops with manure or manure tea or perhaps let a dog or cat or chicken into the garden. All of these habits have the potential to make you very ill. Some who are at highest risk could even die from related illness.”

Growing produce in your home garden or fields does not necessarily mean your food is safer than commercially grown food. Following the same bad practices will result in bad outcomes. And organic or conventionally grown is not the issue. Ballard says those are somewhat irrelevant terms when discussing food safety.

“Microbes really don’t care which set of production practices you use,” he says. “They are opportunistic and will find places where they can flourish under either system. Manure is manure. [Wild] bunny manure should be considered the same as horse or cow manure. Compost is a great soil amendment, but compost must be done in a controlled and monitored way to assure that the material actually heats up and becomes pasteurized. Just piling up manure and leaves and kitchen scraps for a few months is not composting. That is manure and not compost.”

Microbial contamination is the main safety concern when growing and harvesting crops, Ballard says.

“The key is to limit exposure of edible crops to microbes: Harvesting them in a way that keeps them clean, cool them to retard growth, and market or use them in a way that preserves the quality and safety until they reach the fork,” he says. “Really think about all the places where microbes can contact your food all along the production, harvest and preparation process. That chain of quality, safety and cleanliness has to remain unbroken from start to finish.”

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If you’re heading out to the field or garden, keep in mind these points for preventing food-borne illness in the crops you grow:

1. Manure Application
Do not apply manure to crop areas near harvest times. Several months should pass between manure application and harvest. “Ideally a fall application prior to the harvest the next growing season,” Ballard says. “Do not manure tea or manure side-dress.”

2. Flood Waters
Floodwaters can contain a host of bacteria that may make the food unsafe or cause spoilage. Soil contamination from flooding may be as high as uncomposted manure so treat a flooded field as if it had a manure application. Allow a minimum of 120 days between the recession of waters and harvest to reduce contamination risk. When in doubt, throw out food that may have been damaged or spoiled in the flood. It’s risky to eat any of the produce, so discard it for safety’s sake.

3. Contamination Avoidance
During the growing season, take steps to limit your crops’ exposure to dangerous microbes. Keep animals—both wild and domestic—out of gardens. Use supports for crops to raise them off the ground. Any crop that has direct contact with the soil or soil splash or flood waters is at a high risk for contamination, so use drip irrigation or soil-applied water. Avoid overhead irrigation.

4. Irrigation 
Use potable water to irrigate. “Municipal is best, groundwater second-best and then surface water,” Ballard says.

5. Harvesting Tools
Use clean, dedicated, sterilized buckets for harvesting, not ones that had hydraulic fluid or paint in them. Use clean knives and scissors when harvesting, avoid wounding produce at harvest, and discard any produce with damage or bird droppings. “If in doubt, throw it out,” Ballard says.

6. Cleaning Produce
Rinse produce well with tap water. This removes soil and perhaps some attached pathogens, but does not guarantee safety. Store fresh produce in cool conditions to reduce microbe growth. For more information on washing and handling produce, consult the University of Minnesota Extension’s “Washing Fruits and Vegetables—Why and How” by Debra Stolpa and the Food and Drug Administration’s “Produce Safety: Safe Handling of Raw Produce and Fresh-Squeezed Fruit and Vegetable Juices.”

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