A study of bacterial inhibitors for cutting oils and a proposed new method for testing bacterial inhibitors in emulsion type cutting oils

A procedure is recommended for testing bacterial inhibitors in soluble Oils* The test is divided into two parts: 1) a closed system screening study carried out for seven days, 2) an open system test for a longer period of time to determine the effective life of the inhibitor. The closed testing system is carried out to determine potential inhibitors to® use in cutting emulsions* The soluble oil emulsion is mixed with a desired concentration of inhibitor. The volume used is 19.0 ml of the oil emulsion and inhibitors and uninhibited controls are then sterilized. The tubes are inoculated with 1.0 ml of used oil emulsion which has been collected Just prior to use. The inoculated tubes are mechanically agitated on a laboratory shaker at room temperature for the 7 day screening period. Immediately after inoculation, and at 24 hour intervals thereafter, 0.1 ml amounts of the emulsion are Inoculated into nutrient broth The inoculated broth tubes are incubated for 48 hours at 37°C and examined for turbidity. [...]