Heavy rains followed by flooding can negatively affect plants in the garden. When plants are exposed to floodwater for prolonged periods of time the roots are deprived of oxygen and the plants can suffocate and die. For vegetables and other tender plants, several days of flooding can cause rapid rotting and death. In addition, contamination of fruits and vegetables by floodwater can create a food safety hazard.
Floodwaters commonly contain microbial contaminants and can directly affect public health. Microbial contaminants may include bacteria, viruses and parasites. Common foodborne pathogens reported in floodwater include norovirus, Salmonella, Escherichia coli, Cryptosporidium and Giardia. Following Hurricane Katrina, fecal coliform concentrations increased in floodwater at all locations tested in New Orleans. Floodwater exposed to raw sewage, farm animals (such as chickens or goats), river or pond water and agricultural runoff is likely to carry harmful pathogens and parasites and thus spread health risks to fresh produce in your home garden.