Food Safe Questions

[Rick-U]

Hello All,

I'm starting to turn items intended for direct food contact, and I could use your wisdom in this area.

1. How about spalted wood and food? I like mushrooms but can't tell a good one from a bad one.

2. If there is nothing on the label that proclaims FDA approval, how can one safely choose a finish? I am aware of products such as salad bowl finish and others that are expressly marketed for direct food contact, but would like a bit more flexibility if I can do so safely. For example I plan to use Mineral Oil for salad bowls, but would like to have a shinier finish for some other items than it offers.

I currently like the results I get with pure tung oil which I understand to be food safe. However, I initially apply it diluted with 2 to 3 parts paint thinner. Does that ruin it for food contact?

I also understand boiled linseed oil is food safe, but I also have heard about problems with some of the drying agents used.

Thanks in advance for taking the time to share what you can. I've found some articles, but always appreciate what the real experts have to say.

 

[MichaelMouse]

Faith and science bump heads here. If you are a zero tolerance type, no finish will meet your demands. If you are a pragmatic type, almost all will, because when cured, they are virtually indigestible, assuming you do ingest them somehow, and extremely proof against leaching, though anyone who keeps liquid in wood is going have other problems. The treatment favored by the zero types is mineral oil, which never cures, and is therefore a a potential shelter from detergents for bacteria, subject to bleeding in the sun, and takes the dirt right off your fingertips if it's oil soluble. Mixing with beeswax, which contains an antibacterial residue from honey might improve it.

Best answer to give, after referring you to 21CFR175.300 (Title 21, Code of Federal Regulations Volume 3, page 162 ff, Part 175 INDIRECT FOOD ADDITIVES: ADHESIVES AND COMPONENTS OF COATINGS) , is whatever your customer considers food safe probably is, as long as it's cured.

I like oil finishes, because they help reject detergent and water from the wood, keeping it up top where it can kill the real danger - bacteria which might grow in neglected foodstuffs. Walnut oil is my favorite, and though there are some who reject it because of nut allergy danger, it is as safe and easy as anything out there. Nut allergies are to protein, not oil, and solvent-extracted oils contain no protein. The health food types which are cold pressed might, but a bit of heat short of ignition in the microwave should denature them handily for that one tenth of one percent of the population which might have reactions to tree nuts. If they were there in the first place.

The danger of allergic reaction to spalted wood is going to be greater than to nut oils, so those are best covered with curing finishes, and the customer advised that they are "dry" bowls, because of mycotoxins and antibiotics they may contain.

 

[Russ Fairfield]

Read this article from Popular Woodworkinmg, by Bob Flexner. It tells you everything you need to know about finishing wood that will be used for food service.

http://www.popularwoodworking.com/features/finish3.html

The problem is that "food-safe" has everything to do with perception and nothing to do with fact. Appearance and smell are inportant factors. I use two rules. If I have to explain the "food safety" of the finish, the sale is lost. If it smells like paint, they will never ask the question.

Appearances are everything, and spalted wood looks dirty to the prospective buyer or user. Again, we should never have to explain the safety of the wood.

You can read my opinions on what makes a good salad bowl at:

http://www.woodturner-russ.com/SaladBowl.html

 

[Rick-U]

Sage Advice

Michael and Russ,
Thumbs up to both of you for really helpful responses. Your helpfulness is above and beyond expectations, and if I can stay out of trouble, neither of you should ever be named as codefendants. 😉