Food Safety for Food Crop Producers After Flooding

Flooding is considered the flowing or overflowing of a field from open bodies of water outside the food crop producers control. Flood events can pose significant public health risk. Floodwater may contain any number of different unknown hazards.

Even if a crop is not completely submerged, there is potential for contamination. It is important to consider all types of potential contaminants including sewage, chemical hazards, such as heavy metals and toxic agrochemicals, or biological hazards, such as bacterial pathogens, parasites, and viruses.

Can The Plant Uptake Contaminants Through The Roots?

• Chemical contaminants: Some studies on the variability in uptake among vegetable types show that leafy greens have the greatest potential to accumulate heavy metals, followed by root vegetables and legumes. Request a chemical assessment of the soil to determine its potential for chemical uptake.
• Microbial Pathogens: Some studies indicate that internalization of pathogens (e.g. E.coli O157:H7) is possible in spinach and lettuce leaves through stomata or physical blemishes on the plant. Studies are insufficient to indicate whether human pathogenic bacteria could contaminate the harvestable portion of a crop by being taken up by the plant through the roots.

What Should Be Done With Crops Contaminated By Floodwater?

Crops exposed to floodwaters are considered adulterated. The US Food and Drugs Administration (FDA) recommend that these crops be disposed of in a manner that ensures they are kept separate from crops that have not been flood damaged to avoid adulterating clean crops. There could be health implications or legal issues if a person consumes the product or feeds it to livestock, so it must be disposed of in a way that ensures that it will not enter in the food chain.

What Can Be Done With Product That Has Been Damaged, But Not Exposed to Floodwaters?

In the case where a flood is imminent, certain crops can be harvested early and delivered to an alternative market. Having a secondary market established can save some time and money during an emergency. Factors to consider:

• Identifying potential processors that are not in the same geographic area as the farm since operations close by may be damaged or without power.
• Pickling plants, especially those supplying specialty markets, may be interested in premature fruits and vegetables such as green strawberries and tomatoes.

• Processors, in particular, jam and jelly processors may be interested in premature or damaged fruits.

The definition of Adulterated means to make something poorer in quality by adding another substance, typically of inferior quality. While the official definition by the FDA, in the context of flooding can be defined as " it bears or contains any poisonous or prejudicial substance which may render it injurious to health...''.

Can Grain from a Flooding Bin Be Salvaged?

If a grain bin is flooded, it may be possible to salvage de portions above the water immersed grain. To prevent cross-contamination, salvageable grain must be removed from the top or side, not down through the contaminated grain.

Aeration fans could spread mold or other contamination. FDA allows for reconditioned in cases where the floodwater did not remain long and rare situation where it is known that the water did not contain contaminants.

What Types of Microbial Contamination Could Be In Surface Water?

The type and concentration of microbial pathogens in floodwater are dependent on factors such as human and animal activities in the vicinity flood area and the source of contaminants.

After flooding, assessment of microbial and chemical quality of surface water is necessary before using the water for agricultural purposes. The use of contaminated water for irrigation and other pre-harvest activities will increase the risk of microbial and chemical contamination.

Frequently reported bacterial pathogens in floodwater include: E.coli O157:H7, Salmonella, Vibrio, Campylobacter, fecal Streptococcus and Enterococcus.

What Can Be Done to Prepare and Minimize Impacts on the Farm?

Producers staying on the farm during a storm will need to make sure they have enough supplies for themselves as well livestock.

• Test chain saws ahead of the storm, fill with gas, and have extra gas ready.
• Prepare wells and other water sources for potential flooding. Have batteries and flashlights ready.
• Have tarps, rope, and duct tape on hand.
• Know exactly where gas, electrical, and water cutoffs are. In some cases, emergency personnel may ask for utilities to be turned off ahead of a storm to prevent explosions, electrocutions, and contamination to the water supply.
• Take photos to document crops and equipment before storm.
• Keep a copy of important documents off site or in cloud storage. This information will be essential for filling an insurance claim or applying for federal assistance.

Reason Number 1 to Handle Your Crop Safety After Flooding:

It may save a life!

Funding for this publication was made possible, in part, by the Food and Drug Administration through PAR-16-137. The views expressed in written materials or publications and by speakers and moderators do not necessarily reflect the official policies of the Department of Health and Human Services; nor does any mention of trade names, commercial practices or organization imply endorsement by the United States government.