Are my black walnuts safe to eat?


I harvested some black walnuts from a tree in my yard. After removing the husks and letting them dry for a couple weeks, I put them in an uncovered plastic box. Now some of the nut shells have white mold on them. Can you advise me if they are safe to eat?


Viña Lindley, Food Systems & Home Horticulture Professional

Unfortunately, I would recommend that you discard the black walnuts. The molds that grow on nuts and other seeds (grains) are more likely to be aflatoxin producers which are toxins that can be carcinogenic. While you may not be able to see mold on the inside of the shells, it is possible that parts of the fungus are still present on the nut meat.

If you decide to try harvesting and processing black walnuts again in the future you’ll want to be sure to cure them for several weeks in an area that is well-ventilated and away from direct sunlight and once they are dry store them in mesh or burlap bags somewhere cool and dry. Another option, once the nuts have dried, is to remove the shells and store refrigerated or frozen. Properly cured black walnuts should store well for up to a year.