“...I've not noticed any sign of 
fungus in them.”

I use blo on pretty much everything, I live in Ireland where its always damp, no
central heating and the only place that fungal growth has ever been apparent is
on some of my carving tools that I keep in a  drawer in my house - they rarely
see the light of day- the drawer thickness and length is just big enough to fit
the tools in, I have noticed very slight fine whitish fungal film on the
handles, I have wooden planes and heaps of other wooden handled tools in the
same cabinet in larger drawers and cupboards and there is never any sign of
mould. Keep meaning to chuck in a couple of silica sachets in the said drawer -
that should help …right?