C41 developing - Pink/Magenta stain issue on some frames of the film

[MattKing]

The stabiliser that comes in C-41 presskits

Probably older technology - note the use of the term "stabilizer".
And just because you don't have problem with environmental bacteria .....

 

[mshchem]

Fuji EU uses Miconazole in E6 final rinse. Commonly used antifungal.

 

[lantau]

The stabiliser that comes in C-41 presskits always leaves white residue spots on the film. I can wipe them off the non-emulsion side with some isopropanol, but it is tempting to give a quick dunk in a PhotoFlo solution after the stabiliser.
I've got many years worth of XP2 developed in B&W chemicals that has never seen stabiliser. No signs of fungus even on the oldest (kept in plastic sleeves).

XP2 developed in b/w chemistry gives a silver image. Silver is a heavy metal and highly toxic to microorganisms. No need for preservatives.