EFFECTS OF SALT AND SERUM ON THE SPORICIDAL ACTIVITY OF LIQUID DISINFECTANTS

This study compares the effects of various concentrations of salt or s erum in the killing of Bacillus subtilis spores by either glutaraldehy de, sodium hypochlorite, cupric ascorbate, hydrogen peroxide, peraceti c acid, formaldehyde, or phenol, Salt affected only glutaraldehyde, it s sporicidal activity increasing with an increase in concentration of sodium bicarbonate or sodium chloride. The sporicidal activity of glut araldehyde was minimal when the concentrations of aldehyde groups and lysine residues from protein were similar, We present an equation desc ribing the effect of serum on spore survival as a function of glutaral dehyde concentration that fits the data with a regression coefficient of 0.9. Cupric ascorbate and peracetic acid were inhibited by serum, b ut this effect was linked to a rise in pH. Sodium hypochlorite was the agent most sensitive to protein, with its sporicidal activity nearly disappearing in the presence of 2% serum or an equivalent amount of pu rified protein.