Antibacterial Activity of Tissues of Bivalve Molluscs Available on Polish Market

One hundred and ninety seven samples of molluscs representing different species were tested for the presence of antibacterial substances using a microbiological diffusion test - “4-plate” method. It was found that 58 samples (29.4%) were positive. The percentage of positive samples depended on species and varied from 0 (Ostrea edulis, Perna canaliculis, Cardiumedule, Myretrix lyrata, Mercenaria mercenaria) to 41.2 (Mytilus edulis) and 50.0 (Tapes semidecussatus and Ruditapesphillipinarium). The randomly performed confirmatory analyses using HPLC -MS/MS method did not show the presence of any known antibiotics.