Use of black walnut for salad bowl

bfwhitma · Dec 2, 2009

I need your help. I have always avoided using black walnut for a salad bowl because of the juglans toxin to plants that all gardeners know about with respect to this tree. I now have a person who wants badly to use a walnut bowl I turned for salad and I thought of applying 3 coats of a top quality salad bowl finish like Behlens on the assumption that if the FDA leach test proves the finish to be non-toxic when dried, then any substance in the wood under the coating would be blocked from transfer as well but you all may have better information on this.

Thanks for your thoughts.

Brad

Barbara Gill · Dec 2, 2009

Brad, during all the years I have been turning I have never heard of someone being poisoned by their Black Walnut bowl.

DMcIvor · Dec 2, 2009

I might misunderstand your point, but I think you may be confusing two issues.

The juglans toxicity is specific to plants, and a good reason not to grow walnut trees next to your garden plot, and to think twice about dumping a lot of walnut shavings into your mulch pile (a little in the mix has never caused problems for me).

The other problem with walnut is associated with nut allergies that an increasing percentage of our population seems to be experiencing. But like Barbara, I've never heard of anyone reacting to use of the wood, even in contact with food.

robo hippy · Dec 2, 2009

When I sell a black walnut bowl I tell the people a few things. One is that walnut is very strongly scented, and will/can add flavor to whatever you are eating out of the bowl. This can drive some people nuts, and others love it. The smell will fade eventually. I don't think I would like to eat soup or ice cream out of a walnut bowl, but with salads, the flavor would be an enhancement. Some people do react to the walnut wood, and some to the nut allergies. They are two different things to be allergic to, and one could be allergic to one and not the other, or both.

robo hippy

MichaelMouse · Dec 2, 2009

If you have a continuous film finish you aren't really concerned about the wood, because it's merely a substrate. LOTS of lacquered walnut bowls sold down in Missouri, I can assure you. I even own one.

Now, if you are going to apply a treatment like wax or a non-curing oil to the bowl, 'nother matter. The stuff that tickles your nose can dissolve in the finish and the salad oil and stick around for a while. If you don't mind a bit of spice, I suppose it's no problem.

As far as allergies go, it's normally to the proteins. Your body sees them as foreign and potentially dangerous, and mounts an immune defense against them that can include all the usual symptoms, like urticaria (hives) and, histamine, which can be dangerous if it causes swelling in your throat and trachea. Protein is not a part of the wood, and if the AAAAI is correct, not of the oil, either, but there are plenty of oil-soluble chemicals that can cause everything from a sneeze to a rash. That's the "sensitivity" reaction.

Juglone is for reducing competition for nutrients from other vegetation. Made mostly in the roots, husks, and some leaves. http://www.wvu.edu/~agexten/hortcult/fruits/blkwalnt.htm May be a sensitizer, and I'm sure if you actually ingested a mess of it, it might do something bad, but I'd also bet the LD50 is pretty high. Least of the worries.

Donna Banfield · Dec 2, 2009

Brad, before I discovered woodturning, I bought a large walnut bowl at an art fair about 15 years ago. The finish was urethane oil. I've used it for salads, chips, popcorn, countless times, and never suffered any ill effects.

Over four years ago, I turned 2 8" walnut bowls that my husband and I use for salads 2-3 times a week. The salad dressing gets poured right into the bowls.

bfwhitma · Dec 6, 2009

Thanks as always

Thanks as always. Your advice was corroborated by a PhD biologist friend of mine who knows the juglans species and their adaptive behavior of protecting the area around their roots with the growth inhibitors that apply to foreign seedings but not its own and they are not identified as human toxins. Nature is great. My walnut bowl lover will be happy.

Jerry Hall · Dec 6, 2009

All wood is toxic I am told

if consumed in sufficient quantity....Like a lot! But fortunately except maybe for cinnamon it doesn't taste so good.

Nate Hawkes · Dec 8, 2009

bfwhitma said:
Thanks as always. Your advice was corroborated by a PhD biologist friend of mine who knows the juglans species and their adaptive behavior of protecting the area around their roots with the growth inhibitors that apply to foreign seedings but not its own and they are not identified as human toxins. Nature is great. My walnut bowl lover will be happy.

Well, this is partially right. Walnut does have an allelopathic chemical--juglone, which inhibits the growth of some--not all--plants around its roots. However, there are quite a few people, myself included, who can and do react to juglone on their skin. I break out in a severe contact dermatitis (think poison ivy rash so bad it sends you to the doctor to get steroids) from pretty much any prolonged contact with fresh shavings, and get a little wheezy from dust when I'm not wearing a properly fitting respirator. For whatever reason, my hands don't seem to be affected very much at all. They get stained, but don't really itch (much--I do notice it). This is a bummer for me, as I love walnut--its about my favorite wood. I mill all my own lumber for flat work, and had a severe reaction before I realized what was going on. I thought the tree may have grown around a poison ivy vine (which walnuts will do). This was not the case. I looked up my symptoms online, and found that a fair percentage of people may react with the "juice". I've never had any sort of allergic reaction to any nut, fruit, etc. Its another protein than the juglone toxin at work. Here's a decent article if you're interested:

http://www.immunocapinvitrosight.com/dia_templates/ImmunoCAP/Allergen____28363.aspx

Edit: although all this is important to know pertaining to allergy responses, I have eaten out of walnut bowls with no reaction, and no worry of such. Now, if I were soaking water in a bowl made of walnut, I wouldn't drink it. I think there's sufficient evidence when it comes to finishes that a few coats of pretty much anything is going to provide a pretty good barrier, provided you aren't serving soup or wet foods out of a walnut bowl, which I wouldn't personally do with any wooden bowl for that matter......

robo hippy · Dec 8, 2009

I had a bowl that I carried to craft shows for 10 years, which I retired due to ring check a couple of years ago, which led to a crack. I ate everything available at the shows in it, including soup (hot and cold), cereal, ice cream, cheese cake, bar-b-que, salads, pasta, fish, stir fry, French toast, pancakes, omlets, scrambled eggs, Mexican, pizza, I frequently used it to drink out of as well, and a host of other ethnic foods. They hold up fine. Do not store wet foods in them, especially, not in the fridge. I never oiled it beyond the initial oiling, and soaped it only once in a while. Just what they were designed for. Otherwise, it is art. Oh, no, not that argument again!!!

robo hippy