Effects of lactic acid and chitosan on the survival of V. parahaemolyticus in Mussel samples

Abstract

Lactic acid and chitosan were evaluated for their effects on the growth and survival of V. parahaemolyticus on mussel meat. Mussel (Mytilus sp.) samples were collected from the Samsun region on the middle Black Sea coast of Turkey. Each shelled mussel was decontaminated by immersion in 4% formalin for 3 min. The decontaminated mussel was dipped in TSB broth containing between 8.25 and 7.60 log CFU g-1 of V. parahaemolyticus and left for 30 mm at room temperature 25°C to allow attachment. Initial counts of V. parahaemolyticus in mussel meat immediately after dipping in TSB broth were in the range of 5.38-4.03 log CFU g-1. Each inoculated mussel (25°C) was dipped in 0.5, 1, 1.5 or 2% of lactic acid (v/v) or 0.05, 0.1, 0.25 or 0.5% of chitosan (v/v) for 5, 15, 30 or 60 min. Initial counts of V. parahaemolyticus in mussel meat decreased following treatment with lactic acid for 5 min by 1.90, 2.13, 2.27 and 2.78 log CFU g-1, respectively and following treatment with chitosan for 5 min by 1.33, 1.41, 1.56 and >2.03 log CFU g-1 respectively. Growth of V. parahaemolyticus on mussels was completely inhibited after being dipped in 1.5-2% lactic acid for 15 min and 0.5% chitosan for 5 min. © Medwell Journals, 2010.