<jats:p> <jats:italic>Pediococcus pentosaceus</jats:italic> FBB61 and L7230, isolated from cucumber fermentations, produced a bacteriocin, designated pediocin A, which had identical activity spectra against species of <jats:italic>Pediococcus, Clostridium, Staphylococcus</jats:italic> , and <jats:italic>Streptococcus</jats:italic> . Both strains possessed a 13.6-megadalton plasmid (pMD136). Plasmid curing experiments suggested that both bacteriocin immunity and production determinants were encoded by pMD136. Use of pediocin-producing strains in food fermentations is discussed. <jats:sec sec-type="scanned-figures"> <jats:title>Images</jats:title> <jats:fig orientation="portrait" position="float"> <jats:graphic xmlns:xlink="http://www.w3.org/1999/xlink" mimetype="image" orientation="portrait" position="float" xlink:href="aem00146-0207-a" xlink:role="1539" xlink:type="simple" /> </jats:fig> <jats:fig orientation="portrait" position="float"> <jats:graphic xmlns:xlink="http://www.w3.org/1999/xlink" mimetype="image" orientation="portrait" position="float" xlink:href="aem00146-0208-a" xlink:role="1540" xlink:type="simple" /> </jats:fig> </jats:sec>