You don't want the bowls sealed. That can trap moisture and ruin the wood. Wood needs to breathe and maintain some of the natural oils or it can split and check.
I use a food-safe finish on the wood bowls I make... plain old mineral oil. You can get it at most any pharmacy or druggists. Will not go rancid, will not impart any odd taste to whatever is in the bowl. Unless you use so much that is slops over :nono: then you'll get a taste of "green apple quick-step".
I've also used walnut and peanut oil, they don't seem to go bad, but can cause allergic reactions so I stopped using them except if I know that the user isn't allergic. The light super-fine olive oil also works but can impart a very slight flavor- not bad for lunch and dinner, but nasty with frootie-ohs and milk.
A few care & feeding hints for wood-ware, as I send with any of my food-grade turnings:
- NO dishwashers. hand wash only, please.
- Mild soap, mild scrubbers, very little water.
- DO NOT soak, no matter how sticky your wife made the oatmeal.
- Dry thoroughly after washing.
- Lightly oil when dry- inside and out. Then buff with a cotton cloth.
Nothing to it, really. Hope this helps.
vic
