Sterilization of milking machine rubberware

Abstract

Rubberware in good mechanical condition was sterilized satisfactorily with hot water and all of a number of inorganic and organic sterilants tested, but few of the sterilants were effective when the rubberware was in an unsatisfactory condition.
Prolonged immersion in hot water completely inhibited bacterial development whatever the condition of the rubberware. A hot-water rinse was not so effective and its efficacy declined with deterioration in the condition of the rubberware. Heat sterilization did not shorten the effective working life of the rubberware.
The efficacy of caustic soda as a sterilant, which was high with rubberware in good condition, fell off slightly with unsatisfactory rubberware. However, the use of caustic soda tended to prolong the working life of rubberware. Sodium metasilicate was similar to caustic soda.
The efficacy of chlorhexidine, iodophor and organic ammonium chloride solutions was high with good rubberware but declined rapidly as the condition of the rubberware worsened. None of these solutions appeared to erode either rubber or metal surfaces.
Sodium hypochlorite was ineffective as a sterilant even with rubberware in good condition. It eroded the surface of the rubberware, thereby increasing the difficulty of chemical cleaning and sterilizing.