Sporicidal activities and mechanism of surfactant components against spores.

The sporicidal activities of seven kinds of antimicrobial agent were investigated in order to screen for novel inactivation agents to apply to spores. Antimicrobial agents based on surfactant components, as poly-l-lysine, thiamine dilaurylsulfate, and torilin, were more effective than other agents. The degree of spore reduction with 1-2% surfactant components was 1.5-2.5 log CFU/mL. The HLB value (hydrophile-lipophile balance) related to denature protein of spores coat on surfactants with sporicidal activity was ranged from 6 to 16. Average HLB value and spore killing effect was inversely correlated. The proteins on spore structures seemed to be disorganized due to binding between polar groups of coats and hydrophilic and hydrophobic groups of surfactant components, resulting in killing of spores. The components that were effective to inactivate spores had a chemical structure containing CH, OH, COOH, sulfate groups, and a double bond. Furthermore, hydrophobic surfactants were more effective than hydrophilic surfactants in inactivating spores. This was likely due to the type of hydrophobic surfactant and to the involvement of hydrophobic interactions on coat of spores.