Aliquots of the HPLC purified fractions of PlcA were evaluated for their antimicrobial activity and inhibitory spectrum against different indicator microorganisms. Of these only A.acidoterrestris sp1, Lb. bulgaricus UCC, Pediococcus inopinatus 1011 and all tested lactococcal strains were inhibited by the bacteriocin produced by Lb. plantarum NI326 (Table 1). In comparison with other circular bacteriocins, PlcA possesses a narrow spectrum of activity. The low yields obtained during the purification of PlcA may explain the lack of activity against some of the indicators used