My fiancÚ found these amazing old wood school tables (circa 1930s). We want to use them as countertops in our 1910 kitchen, finished with tung oil.

I have planed and sanded the tops which now look beautiful with all the historic distress from the children. I am fine with most of the flaws but there are some which are quite wide (1/4") and some are very deep (1/2" to all the way thru).

I am concerned about food and dirt in these cracks being difficult to clean. I would like to fill them but I really want them to be food friendly.

Does anyone have suggestions for a non-toxic wood filler? Color is not a problem as rustic is the word.