Papers covered with hydrophobic layers (Aquacer, Ultralub) were coated with antimicrobial layers by M. Mizielinska et al. (2018), aged at 120 degrees C for 24 h and studied for antimicrobial activity against E. coli and S. aureus. The papers coated with polylysine remained active against both strains after the ageing which did influence neither the Ultralub subcoating nor the coating with polylysine.