I reviewed 10 scientific papers and some documents from Kikkoman. One of the subjects that comes up has to do with what kind of soy sauce is being produced, Japanese, Chinese or hydrolyzed protein, both Japanese and Chinese traditionally brewed soy sauces seem to benefit from the actions of halophilic yeasts durring the course of fermentation. The articles all conclude there is a strong correalation between desirable quality flavorcharacteristisc and the presence of specific halophilic yeast. None of the articles revealed any specifics about standard methods for enumeration or testing for the presence of these organisms.
In my opinion, other quality specification parameters including pH, brine salinity and organoleptic testing for flavor, color, mouth feel, aroma, defects etc., against a known standard at periodic frequencies during fermentation will indirectly indicate the presence or absence of the desired organisms.
One paper concluded there is an ideal ( approximately 1.5 × 106 yeast per gram of koji) inoculate quantity of the halophilic yeast organisms that if exceeded will inhibit the needed enzymatic activity of the koji enzymes to convert starches to sugar. paper attached
I have attached the singular paper that discusses standards methods for the enumeration of halophilic organisms. The procedures, methods, equipment and supplies seem to be rather complex and sophisticated.