On the practical personal safety level this is easy to answer. If you(or the person you are going to serve it to) have food alergy for any of the categories and you can’t find a “Contains” list then you don’t consume(serve) the item.

Want to make it clear i’m not arguing with this against the current alergen labeling laws. I see it as a variant of Postel’s principle. The food manufacturers should label everything strictly, and consumers affected by any alergy should assume that where there is no information then the alergen they worry about is present. This way the system remains trustworthy while the customers can safely avoid where mistakes are made or packaging gets damaged or smudged or anything like that.