STUDIES ON THE ANTISEPSIS FOR AGAR DURING THE MANUFACTURING PROCESS IN THE MILD WINTER-VI

INFLUENCES OF ANTISEPTICS ON THE QUALITIES OF “TOKOROTEN” AND AGAR

Abstract

As already ascertained by the authors¹⁾, addition of an anticeptic, hydrogen peroxide or chlorotetracyeline, to“tokoroten”, a crude agar, does allow it to be finished into agar proper without suffering spoilage. However, the agar prepared from a “tokoroten” added with an antiseptic was found, in turn, to be reduced in the potency of producing the jelly strength, contaminated with residual antiseptic and possessed with a mood to color in its storage.
From these circumstances, it was tried in the present work to make sure the marginal conditions beyond which said undesirable effects of antiseptic addition to “tokoroten” grow practically serious. The results obtained are presented in Tables 1-4 and summarized as fol-lows:
I. The effect on jelly strength for “tokoroten” and agar:
(1) The marginal concentration up to which hydrogen peroxide can be used without re-sulting in a drop of jelly strength lies likely between 1/10, 000-1/5, 000, at concentrations beyond this limit the fall of jelly strength enlarging with increasing addition of this medical, and especially in the case of agar.
(2) Addition of CTC has no effect at least up to 1/100, 000.
II. Coloring effect:
(1) Addition of hydrogen peroxide at a concentration of 1/4, 000-1/1, 000 is effective for obtaining “tokoroten” as well as agar distinctly white as compared with respective controls.
(2) Addition of CTC at a concentration of 1/100, 000 results in slight darkening of the agar produced despite of its negative effect at 1/200, 000.
(3) As to discoloration of an agar under storage, effect of the hydrogen peroxide added at a concentration above 1/5, 000 to “tokoroten” becomes apparent as a tendency to the disco-loration, the tendency being the stronger, the larger the addition of this antiseptic, while CTC remains to be indifferent, insofar as its addition is smaller than 1/100, 000.
III. Residue of antiseptic in the agar prepared.
(1) Although a “tokoroten” initially added with CTC is possible to retain a great portion of the antiseptic for a long period, it is not impossible to manufacture this “tokoroten” into an agar practically free from the CTC, and that even with ease.
(2) An agar made from a “tokoroten” added with hydrogen peroxide or CTC can be used in the preparation of culture media possessed of no such factors as do harm to the growth of common bacteria. It is considered, however, that an agar still containing residual CTC is not suitable for the preparation of culture media for the CTC-sensitive bacteria.