Flood water contamination

Water, taken in moderation, cannot hurt anybody. - Mark Twain (1835 - 1910)

Contrary to Mark Twain's clever quote, water, even a little, can be quite dangerous. Flood water, be it from storm surges or overflowing rivers, is always assumed to be contaminated. There may be raw sewage, toxic soil, dead animals, and other undesirable extras that were picked up by the flood.

When cleaning up after a flood it's important to keep in mind that even after the water has gone and items have dried out, the germs and toxins carried by the flood water still remain. Food items that came in contact with water should be disposed of. The exception is commercially sealed cans which are undented, free of rust, etc.

To disinfect undamaged cans, remove paper labels (paper can harbor bacteria) and
re-label with a permanent marker. Wash the containers in warm, soapy water and use a brush to scrub surfaces. Rinse well in clean water. Immerse the clean, rinsed containers in a household bleach solution (two tablespoons bleach per one gallon of water) for 15 minutes. Air-dry cans before opening or storing. Use foods from disinfected containers as soon as possible because cans may rust. Commercially canned foods can also be boiled for 10 minutes as a disinfection treatment, but avoid this treatment for carbonated beverage cans. - University of Maine Cooperative Extension

Bottom Line
Treat flood water as filth and assume everything it touches is contaminated. You have just two choices for items that were soaked by flood water: disinfect or dispose.