Hey friend,
Racemosa is generally considered the most toxic of the three common North American elder groups. All parts, including ripe berries. The berries from what I have read in traditional
native american and other resources are rendered safe to consume by thorough cooking or long, warm fermentation.
"Red elderberries were traditionally harvested and processed for food by virtually all the Native American groups throughout the plant's range in the Pacific Northwest (Gunther 1945; Turner 1995) for several thousands of years (Losey et al. 2003). Berry laden branches were bent to the ground using hooked sticks and entire berry clusters were broken off and placed in baskets. When several baskets were full, the berries were stripped off of their stems and steamed or boiled in bentwood boxes, small canoes, or skunk cabbage lined pit ovens for several hours. The cooked berries were then spread out onto skunk cabbage leaves to dry above a hot fire or in the sun to make berry cakes (fruit leather), which was often stored until the winter before being consumed (Boas 1921; Gill 1984). Though abundant, elderberry fruit was considered second rate and was often mixed as a bulking agent with better tasting berries. During the historic period many Native Americans steamed Red Elderberries in steel pots, sweetened the fruit with sugar, and canned them in glass jars (Turner 1995). Red Elderberries are very seedy and the Kwakwaka’wakw, who generally believed it was rude to drink
water during or directly after a feast, made an exception for Red Elderberries so that people could rinse the seeds out of their mouth (Boas 1921, pgs 564-566). Today few people eat Red Elderberries on account of their slightly bitter-pungent flavor."
https://arcadianabe.blogspot.com/2013/07/red-elderberry-experiment-1.html
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