Sanitary and bacteriological study of common carp reared in ponds supplied with biologically pretreated sewage

Abstract

Common carp of 300-400 g ind^-1 reared in the ponds supplied with pretreated wastewater from the sewage treatment plant (domestic and fruit and vegetable processing effluents) contained low TVC 20°C and TVC 37°C. Coliform bacteria were only seldom found in the fish muscles, fecal streptococci in liver, and Clostridium perfringens in the gut. However, in tissues of table fish (about 1 kg ind^-1), densities of indicatory bacteria were 10-1000 times as high. Transfer of the fish from the most polluted pond 1 to the cleanest pond 4 for the last 28 days before the harvest caused considerable reduction of bacteria counts in carp intestine and flesh. Quality of flesh of the transferred fish was similar to that of the control fish reared in traditional fish ponds.