The bacteriological quality of water and fish of a pond system for the treatment of cattle feedlot effluent

Abstract

A cattle feedlot waste system consisting of a high-rate algal pond and a fish pond was regularly sampled for bacteriological analyses. High numbers of aerobic and anaerobic bacteria and potential pathogens (e.g. Salmonela spp.) were present in the waste water. The waste treatment system reduced all bacterial groups by more than 99·6%. The skin, gills and intestines of the waste-grown fish housed large numbers of bacteria, including potential pathogens. However, similar bacterial numbers, including potential pathogens, were associated with the skins, gills and intestines of naturally-grown fish, which suggests that the health risk involved in the consumption of waste-grown fish might not be substantially different to that of natural fish populations. In both cases the tissues and blood appeared to be sterile, which would contribute to a much reduced health risk.