Flood waters can carry potential contaminants from nearby areas and spread it over a wide area. If you farm on land with a recent history of flooding, soil should be tested before crops are grown. Consider testing soil for coliforms and heavy metals before crops are grown. If the edible portion of a crop is exposed to flood waters, the produce is considered adulterated under section 402(a)(4) (21 U.S.C. 342(a)(4)) of the Federal Food, Drug, and Cosmetic Act and should not enter human food channels.
When assessing the level of risk posed by flooding, some factors to consider are:
• Whether the crop grows close to the ground (e.g., leafy greens) or does not (e.g., tree or vine crop)
• If the edible portion comes into contact with the soil or flood waters
• Potential sources of contamination in the flood plain (e.g., raw manure)
• Timing of the flood - whether the flood happens in the spring before planting or a flood that occurs when the crop is in the field
To reduce risks when planting after a flood: allow soil to dry out, till thoroughly, allow time for microbial pathogens to decline (the longer the better), add organic matter to promote decomposition of biological contaminants or sow a cover crop.
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The LSU AgCenter and the LSU College of Agriculture