As I understand it, the eating of raw flesh wasn't a practice among the peoples of Finland, the way it has been with some peoples of Siberia or the Arctic Americas. However, we know the Sami at least were aware of the problems posed by scurvy, and had various foods they would eat to stave it off, especially during the dark winter months. Such foods would have included pine bark flour, birch sap, various plants (such as sow thistle and sorrel) boiled with the milk of reindeer to produce a cheese-like food called
gompa. The roots of angelica and
Cicerbita alpina were dried and chewed on throughout the year, as much for their flavor and for amusement as for their nutritional / medicinal properties.
There's more written here:
https://uu.diva-portal.org/smash/get/diva2:565327/FULLTEXT01.pdfBerries too were preserved, mostly by submerging in water to make something akin to vattlingon which is still consumed today (I have also heard of preservation in reindeer fat instead of water). For preserving in water, any combination of berries could be used, but you would at least need to include either lingonberries or cloudberries or both in the mixture: they are the berries that contain the highest amounts of oxalic acid, and that would be the agent mostly responsible for making sure the berries do not rot in the water.
Currently, we do not have mechanisms in the game to preserve berries or plants or whatever. My personal opinion is that it would be a little unfair to add a disease (which would have been well-known and preventable even in those times) to the game without giving the player a chance to do something about it. Not to say I wouldn't welcome it as a possible addition to the game, merely that the decision whether and how to develop it is not something that's up to me.