Damn, came here hoping there would be more chapters to read now that the anime is finished.
Unfortunately, seems the anime was way ahead of the translated chapters.
From how they described it, it sound more like "indentured servitude" than slavery.
Apart from criminals, people get into that position to clear their debts.
The "owner" is also legally bound by laws to provide proper care.
Its not like they are property without rights.
Sure, there will be bad...
There is already an manga/anime called "Isekai Izekaya". Technically, its full name is "Isekai Izakaya "Nobu""
And the MC is pretty much introducing yoshoku cuisine to this new world.
To be short, "yoshoku" is western food as adapted and made by the Japanese.