ASTM D4783-01(2013)

5.1 These test methods are used to demonstrate whether an adhesive preparation is sufficiently protected with biocide to resist attack by bacteria, yeast, and fungi during its storage life. They are patterned after methods used by biological laboratories serving the adhesive industry.

5.2 These test methods may also be used to determine the efficacy of different biocide systems against specific microorganisms.

5.3 These test methods are especially useful when tested against wild-type microorganisms which have been isolated from contaminated adhesives as an aid in determining the amount and type of biocide necessary to kill or inhibit the growth of the contaminants. If an isolated microorganism not generally used as a challenge organism, is chosen as the inoculum, it is important to identify the organism and determine on which medium and under what conditions it will grow, in order to demonstrate the efficacy of the biocide.

5.4 The results obtained when using the procedures given in these methods apply only to the species which are used for the testing. The test species listed in Section 5.5 The presence of an active biocide carried over from the adhesive specimen to the agar could have an inhibiting effect on the growth of microorganisms, resulting in no growth during the span of a normal incubation period, when in fact, viable microorganisms are present, but their growth has been slowed down or held in stasis. The use of Letheen agar and broth is recommended to neutralize the effect of this carry-over.