They left me without the Milk, so... yup, I just cooked them in the Dark Cauldron.
That was in the early days of me earning enough Gold for Lona to leave as a virgin, the times I've run out of smoked meat made me desperate, so I tried it out via Save Scumming.
Of course, I haven't figured out what to do with "Specimens" at the Fishkind Research Quest, as I don't have any Milk on me and Elise is imprisoned during the quest. 😅