A Study of the Nature, Growth and Control of Bacteria in Cutting Compounds

Abstract

Cutting compounds in machine shops have very high bacterial counts due to Pseudomonas oleovorans, which was found almost to the exclusion of all others. The principal morphological and physiological characteristics of this species are descr. In laboratory expts. it was found to grow rapidly in the oil emulsions with no extraneous source of food. It grew on a soln. of 1% crude naphthenic acids in Locke''s soln., with 0.1% KNO3 as a source of N, and probably used naphthenic acids in the oils as a source of C.[long dash]Coal tar disinfectants, although immediately bactericidal, soon become ineffective because taken up by the oil phase of the emulsion. Of many other disinfectants tried, resorcinol proved most effective and usable; a concentration of 1% insures sterilization, but as little as 15 lbs. per month for a 500 gallon tank was found sufficient to prevent spoilage. Oil dermatitis is not due to bacteria, but probably to clogging of hair follicles and pores of sebaceous glands.