Evaluation of glutaraldehyde and hydrogen peroxide for sanitizing packaging materials of medical devices in sterility testing.

External surfaces of packaging materials used for sterile medical devices may introduce contaminants into working areas used for sterility testing. Light wiping with tissues moistened with alkaline 2% glutaraldehyde (Cidex) or 3% hydrogen peroxide effectively reduced counts on 5 X 8 cm strips of packaging material (Tyvek) inoculated with 10(7) spores of Bacillus subtilis. The ability of antimicrobial agents to penetrate packaging material and kill contaminants on the medical device was tested by inoculating filter membranes with ca 100 cells of Pseudomonas aeruginosa or Staphylococcus aureus or ca 100 spores of Bacillus subtilis. A sterile square of test packaging material placed over the inoculated membrane (direct method) or 0.5 cm above the membrane (indirect method) was wiped with the antimicrobial agent. Except for polyethylene film (3 mil), all materials tested, including glassine and several types of coated and uncoated Tyvek, were penetrated by the agents, killing cells on the inoculated membranes. Death rates varied, depending on the organism, packaging material, and testing method. It is suggested that penetration tests be performed before using antimicrobial agents for sanitizing packaging materials during sterility tests.