Bacteriology of the fresh water bivalve clam Batissa violacea (Kai) sold in the Suva market

Abstract

Forty samples of freshwater clam (Batissa violacea), popularly known as Kai, collected from the Suva market were analysed for total aerobic plate count and total coliforms. The heterotrophic bacteria isolated by plate count were also characterised up to genera. The results indicated higher than acceptable level of plate count and coliform bacteria. While total plate count of aerobic heterotrophic bacteria ranged from 5.5 x 105 colony forming units (cfu) per gram to more than 107 cfu/ gram, total coliform load varied between 1.1 x 104 to 1.1 x 105 per 100 gm of Kai flesh. The characterisation of the heterotrophic bacteria revealed the predominance of the genera Micrococcus (34%) and Bacillus (24%). Other genera encountered included Acinetobacter, Vibrio, Aeromonas, Alcaligenes, Pseudomonas, Streptococcus and members of the family Enterobacteriaceae. The results revealed the need for depuration of the Kai in clean running water to reduce the bacterial load to acceptable levels. Temperature control soon after harvesting by proper icing and thorough cooking of the Kai before consumption is also recommended.