4.1 Spoilage of paint in the container can result in putrefaction, lowered pH, gas formation, and decrease in viscosity. This test method provides a standard procedure for the evaluation of the resistance of emulsion paints to microbial deterioration. The results should enable: (1) the paint manufacturer to select an effective preservative and (2) the supplier of preservatives to evaluate the performance in emulsion paints of competitive and developmental preservatives.

4.2 This test method should be used preferably by persons who have had basic microbiological training.

Note 1: The reliability of the results obtained from this test method is extremely dependent on the techniques employed. Improper techniques can result in a sterile sample appearing to be contaminated, and even worse, a contaminated sample appearing to be sterile (see also Note 2). It is recommended that you consult with your biocide supplier, raw material supplier, or an independent testing laboratory to confirm questionable results. Formulation and raw materials' quality may also vary and thereby affect the test results.