Potential of an antibacterial ultraviolet-irradiated nylon film

The antibacterial effectiveness of an ultraviolet-irradiated:nylon 6,6 film was investigated for potential use as-a food-packaging material to reduce the surface microbial contamination of foods. The film-surface analyses sho wed that UV irradiation induced conversion of surface amide groups to amine s. Irradiation also increased the dimensional scale of the film surface top ography (depth: of valleys) approximately 5-fold on the scale of nanometers . The irradiated nylon demonstrated antagonistic activity against Staphyloc occus aureus 25923 and Escherichia coli TV 1058 with 4.5 and 6 log reductio ns, respectively, of an initial population of 10(6) cfu ml(-1). The irradia ted nylon was ineffective against Pseudomonas fluorescens 13525 and Enteroc occus faecalis 19433 under similar conditions. The film demonstrated increa sed antimicrobial activity against S. aureus 25923 with increasing temperat ures up to 45 degrees C, the highest temperature tested. Protein and salt i nhibited the antibacterial nature of the irradiated film. Amines in solutio n (4.31-x 10(-8) M; the calculated equivalent of amines on the film) killed at least 1 x 10(4) cfu mL(-1) E.coli TV1058, and 4.31 x 10(-7) M amines ki lled up to 1 x 10(7) cfu mL(-1) E. coil TV1058. The amines in solution requ ired similar exposure time to the bacteria for population reduction as was observed with the irradiated film. (C) 2000 John Wiley & Sons; Inc.