A differential adenosine triphosphate test method for differentiating between bacterial and fungal contamination in water-miscible metalworking fluids

A new variation of a method for quantifying cellular adenosine triphosphate (cATP) is described. The variation permits differentiation between cATP from bacteria and cATP from fungi. This paper describes the process by which the new differential cATP method was developed and validate in both laboratory and field tests. Laboratory tests using bacteria, yeasts and filamentous fungi demonstrated that cATP observed in >= 5 mu m and <5 mu m size-fractions, respectively were consistently within +/- 10% of predicted concentrations. The field evaluation during which four participating metalworking fluid (MWF) compounders collectively tested >250 used MWF samples, confirmed that the differential protocol reliably detected fungal contamination when it was present. (C) 2015 Elsevier Ltd. All rights reserved.