Flooding increases risk of foodborne illness from garden produce

Farm Forum

BROOKINGS — Soil in gardens that were recently flooded may not be safe for growing fruit and vegetables, SDSU Extension specialists explained.

“Foodborne illness has been associated with garden vegetables contaminated with floodwaters containing pathogenic bacteria, parasites and viruses, said Joan Hegerfeld-Baker, SDSU Extension Lecturer & Food Safety Specialist.

Hegerfeld-Baker said the more common pathogens involved in these outbreaks include E. coli 0157:H7, Cryptosporidium parvum, Cyclospora, Giardia, Campylobacter and Hepatitis A. All of these diseases make people very ill and in some instances have long-term complications or may be fatal.

Hegerfeld-Baker emphasized that gardeners should not attempt to make an unsafe, flooded garden produce safe by using chlorine bleach or a similar product. “The level of contamination on a flooded garden can be at very dangerous levels,” Hegerfeld-Baker said.

Rhoda Burrows, SDSU Extension Horticulture Specialist recommends that gardeners keep in mind that although pathogens will eventually die out, they can remain present in the soil for months, and can even infect produce planted after the flood. “Depending on the location, floodwaters may contain contaminants such as agricultural or other chemicals; as well as disease-causing organisms from fresh manure, septic systems, and even lagoons,” Burrows said. “If the homeowner knows the area was contaminated with feedlot or septic overflow, it is recommended that no produce be used from the garden for 180 days,” she stated.

What to do with garden vegetables after a flood

Burrows said that any leafy greens that are eaten fresh, such as lettuce or cabbage, should be destroyed. “They are at risk of contamination for at least four months following a flood,” Burrows said.

She added that leafy greens that are typically cooked, such as spinach or chard, should be cut back completely and allowed to regrow before using. Once they regrow, Burrows advised that they be thoroughly cooked before using.

Any above-ground produce, such as peas, beans, squash, melons, or tomatoes that were exposed to flood waters should also be picked and discarded. Using a mulch to shield plants and produce from soil contact can help reduce risk for fruit that is formed after the flood recedes.

She advised that during the four months following the flood, any root crops such as carrots or potatoes should either be discarded, or be peeled and thoroughly cooked. Thoroughly wash produce with thick outer rinds, such as melons and squash, before cutting open.

When it comes to strawberry plants which have been exposed to floodwaters, Burrows advised to remove any blossoms or set fruit. “Any strawberries that are consumed within in the next 120 days from these plants should be cooked before consuming,” she said.

Always a good idea to wash first

For fruit and vegetables that did not come in contact with flood waters, Hegerfeld-Baker reminded individuals that the safest way to protect yourself from foodborne illness is to always wash fruit or vegetables before eating.

“When washing freshly picked produce, use water that is at least 10 degrees warmer than the fruit or vegetable and wash with running water and use friction,” Hegerfeld-Baker said.

She discouraged the use of detergents or chlorine bleach.

Hegerfeld-Baker added that some sprays approved for use on fruits and vegetables are available and may be helpful in removing debris, dirt and surface microorganisms. “However, if the garden produce was flooded, don’t attempt to make an unsafe flooded garden product safe by using a fruit and vegetable spray, chlorine bleach or other product.”

Hegerfeld-Baker and Burrows strongly encourage gardeners to use good personal hygiene practices. Wash your hands before and after gardening. Leave your garden shoes at the door and change clothing after working in a flooded garden.

“Avoid direct contact with floodwaters, including the soil, as much as possible. Young children can be at a high risk for some foodborne illnesses. If a garden plot has been flooded, consider either not having young children in the garden with you, or taking every precaution to utilize good personal hygienic practices,” Hegerfeld-Baker said.

To learn more about food safety, flood cleanup and other flood-related issues visit