Studies on the Bacterial Contents of Public Health Concern in Freshwater Cultured Prawn (Macrobrachium rosenbergii) and Pond Water

Abstract

Quantitative and qualitative analyses of bacterial contents of public health concern in cultured giant freshwater prawn (Macrobrachium rosenbergii De Man, 1879) and pond water collected from five different farms of Phultala Upazila in the district of Khulna were carried out in this study during November 2009 following the ISO standard methods. Different bacterial parameters of 15 prawn and 15 water samples were tested. The total bacterial count (Standard Plate Count) found in prawn ranged from 3.2 × 10⁵/g to 5.70 × 10⁵/g, while it ranged from 1.26 × 10⁴/ml to 1.72 × 10⁴/ml in pond water. On the other hand, total coliforms found in prawn ranged between 43 and 460/g, whereas in water, 43 to 240/100 ml total coliforms were detected. In the case of faecal coliforms, the number ranged between 4 and 43 per g in prawn and 18 and 160 per 100 ml in the case of water. Salmonella was detected both in prawns and water of two farms, while Vibrio cholerae was found to be absent in both the prawns and water. It was revealed that Salmonella spp. were detected both in prawns and water samples from those ponds where raw cow dung and poultry faeces were used as manure during the grow-out period. Total bacterial count, total coliforms, and faecal coliforms were also found to be relatively high in prawn and water from those ponds. The practice of using raw cow dung and poultry faeces as manure and contaminated feed in freshwater prawn farms could have an influence on increasing the total bacterial load and enteric bacterial flora and may also be a source of contamination by pathogenic bacteria such as Salmonella. Therefore, according to the findings of the study, it can be recommended that raw cow dung and poultry faeces should not be used in freshwater prawn farms during pond preparation and the grow-out period, in order to adopt "Good Aquaculture Practice" and produce freshwater prawn safe for human consumption.