The atmospheric pressure surface barrier discharge (APSBD) in air has been used in killing Escherichia coli. We have developed two similar dielectric barrier discharge (DBD) structure types of nonthermal plasma jets (PJ) driven by 5-20 kHz audio-frequency power at atmospheric pressure. At a flow rate of 200 L/h (argon), a stable, arc-free discharge was produced. At 1.5 cm from the nozzle, the gas temperature was kept at 47 degrees C for PJ-1 source and 38 degrees C for PJ-2 source. Some research on sterilization has been carried out and results show that such a plasma jet source as PJ-2 is very effective in the disruption of E. coli. (c) 2005 Elsevier B.V. All rights reserved.