Qn: Casein Glue recognition

Hello all

Is there any practical way to tell if a Casein type of glue has been
used to hold our K-7 together ? It is pinkish-light brown (therefore
definitely not Aerodux)and one failed joint appears to have unusually
little excess or fill that makes me suspect it may have been attacked
(and consumed !) by bacteria,
as it happens to casein in moist environments over time.
a weird observation is that a couple of spillages have rolled up and
detached from the wood at the thick end! I think I recall this being a
casein trademark

Is there any methodology to check for such bacterial attack in
normally inaccesible places such as spar boxes etc ? is a visual check
simply adequate.

I guess restoration / vintage lovers will have some good pointers.

Thanks,

Vassilios
Greece