I was surprised that there's nothing in that article about health concerns. Is it just me here being concerned about the stew getting infected by something?
Basically anything above 60°C (140°F) has the same safety as below 4°C (40°F).
I always treated the "best before" on bags of frozen veggies as "avoid after" and am very happy to discover now that frozen vegetables apparently remain safe indefinitely. This will save me a bit of money.
And now I'm more open to trying this perpetual stew thing too.
I just made soup from a bag of a bean mix that I know is definitely more than 10 years old.
Anything that's been held at 136°F or higher for an hour or so is essentially sterile from a food safety standpoint.
Examples are on-living molecules whether inorganic simple elements or complex thermo resistant proteins leftover from other forms of life like fungi.
That said, there's nothing special in a forever stew that makes it particularly more susceptible to this risk. The toxins don't reproduce (unless there's some fucky crystallization phenomenon, but that's sci fi speculation), and if there is some thermoresistant toxin introduced, then it will probably be dilluted quickly.