Spalted Cutting Board

[cava]

Hopefully this is the correct section to ask this question - if not Mod's please move it.

I have just resawn some Nectarine, with the hope of making a long grain cutting board/cheese board.

The Nectarine has minor spalting which enhances it's appearance, and being a fruit wood I am comfortable with the choice of wood for the application. However, I am not sure about the hygiene side of things (mould and all that from the spalting).

I do not want to totally seal the board, but would prefer a more natural finish such as oil/beeswax etc.

The question is, how safe is spalted wood in this application? Or should I just relegate it towards another project?

Thanks all.

[dusteater]

Interesting question.

[Tahlee]

Here is an interesting read Spalt Your Own Lumber: Health problems associated with spalted wood, and debunking myths - FineWoodworking (http://www.finewoodworking.com/2009/04/26/spalt-your-own-lumber-health-problems-associated-with-spalted-wood-and-debunking-myths)

[doug3030]

Quoted from the article Tahlee linked to above:


Fact or Fiction: finished spalted wood products should not be placed in contact with food.
Fiction! If you dried your bowl before you finished it, the fungus is dormant in the wood. That means that, while not dead, it is no longer reproducing or producing spores. Any current spores in your wood will be sealed in by your finish. There is absolutely nothing wrong with using spalted wood for food items, as long as it is properly dried and sealed.

The article refers to there being no danger if the item is "properly" sealed. But it does not specify what exactly is properly sealed. Is an oil finish enough or does it need to be polyurethane or even something else.

For a chopping board most of us would use an oil finish as other finishes would soon be damaged by the knife blade. I wonder what the author considers as properly sealed?

Cheers

Doug

[cava]

The article refers to there being no danger if the item is "properly" sealed. But it does not specify what exactly is properly sealed. Is an oil finish enough or does it need to be polyurethane or even something else.

For a chopping board most of us would use an oil finish as other finishes would soon be damaged by the knife blade. I wonder what the author considers as properly sealed?



This is the dilemma that I am trying to get my head around.

I really do not want to use polyurethane or similar.

[dai sensei]

...[COLOR=#242121][FONT=merriweather]The article refers to there being no danger if the item is "properly" sealed. But it does not specify what exactly is properly sealed. Is an oil finish enough or does it need to be polyurethane or even something else....

Spalt spors die if properly dried, but they need to be baked until completely dry, not just air dried. When it says sealed, my take would be it is stabilised, that then ensures the moisture cannot re-enter and and any rotten wood is hardened. A cutting board is exposed to moisture all the time and hence I would be stabilising the timber properly, i.e. dry to 0%MC then using vacuum and stabilising resin to completely impregnate it, before using it.

[IanW]

As far as I know, the fungi most commonly responsible for wood spalting don't produce anything liable to be toxic to mammals by ingestion. There is a risk of respiratory problems from inhaling the dust when sanding or sawing it. Having said that, I confess to setting a very poor example by always forgetting to take any precautions when working spalted wood & I ought to know better! As Neil said, fungi can remain dormant in the wood for a long time, & are often reactivated if the wood becomes wet enough (the term 'dry-rot' is an oxymoron, ya gotta have water getting in there, somehow, it's essential to life as we know it). Heating the wood to at least 60 C should kill off any remaining hyphae or spores, but no gaurantees it won't become re-infected, because sqquillions of fungal spores of all types are floating about everywhere, all the time. Fortunately, the vast majority of them are far too specialised in what they'll grow in/on, and are non-pathogenic to us.

Getting re-growth of spalting fungi in your wood is unlikely if it's dried & used sensibly, as it usually takes something like 20-25% MC for most fungi to be able to grow. But it can happen, for example, despite our best efforts to dissuade her, MIL keeps leaving the pine cutting board she insisted on having soaking wet, and the bluestain fungus is loving it, the whole board is going to be solid blue, soon! I guess when you're in your 90s you don't get too worried about these things, particularly when your eyesight is almost totally shot.

Cheers,

[cava]

Heating the wood to at least 60 C should kill off any remaining hyphae or spores, but no gaurantees it won't become re-infected, because sqquillions of fungal spores of all types are floating about everywhere, all the time.

Assuming that the bread/cheese board is assembled, as opposed to unglued boards, can the glue sustain heating to >60 C?

[IanW]

Assuming that the bread/cheese board is assembled, as opposed to unglued boards, can the glue sustain heating to >60 C?

Some won't. Quite a few glues will become pretty soft at 45-50*C, so run a test with some glued-up scrap before you zap anything you've laboured long & hard over! I was assuming that heating the raw material would occur before you begin construction....

Cheers,

[cava]

I understand the rationale of heat treatment prior to any glue-ups, but was hoping to capitalise on Robson Valley's suggested treatment of kitchen implements that had been conditioned in an oven prior to soaking up the oil/wax treatment (2 birds one stone scenario :D).