Blackdog,
Excellent opportunity for the 'mother in law test'. Make several spoons, each of different wood you are worried about and give them your mother in law one at a time about 3 weeks apart. Take the previous one back each time because your just not happy with it and wanted to give her a better one. Don't eat her cooking for awhile, maybe your on a diet. If she's OK your OK, if not keeping trying until you identify safe woods and unsafe woods. If she gets real sick maybe just take that spoon back and give it a rest for awhile. Good Luck
Ah Chip
PS: A wooden spoon story. I garden big in the summer, make and can several hot pepper sauces each fall. A favorite is Habanero

sauce, great marinate for pork chops. Made a batch one time. About 5 weeks later we have in-laws over for breakfast after church, big bunch 9 brothers and sisters, 34 grandkids, house full. The spoon that stired the Habanero sauce got use to stir oatmeal. Its the first time I ever ate oatmeal that made sweat drip off my ears.