Occurrence, problems, analysis and removal of filamentous fungi in drinking water

Abstract

The occurrence of filamentous fungi in drinking water has been known for many years. However, the quantity of scientific literature on the subject is only recently beginning to increase. Filamentous fungi have been considered as annoying contaminants of agar plates used to count bacteria from water. There are various potential issues associated with the fungi-in-drinking-water phenomenon, including blockage of water pipes, organoleptic problems such as odours and taste, biofilm formation, spread of pathogenic fungi, and mycotoxins production. Drinking water raises issues of biosecurity in relation to filamentous fungi and the mycotoxins they may produce. This chapter presents a review of fungi in drinking water, with emphases on (a) methods of isolation, (b) fungi detected, (c) which problems occur, (d) avoidance or removal of filamentous fungi, and (e) methods to detect biochemicals such as mycotoxins. The literature on bottled and domestic tap water will be assessed because bottled water is increasingly being returned due to the presence of filamentous fungi. Suggestions for future collaborative work will be made which will include the use of standardised methodology for isolation and identification of filamentous fungi, the use of "ring tests", standard biochemical analysis, and the need for international research projects. Also, sound methods for the removal and control of filamentous fungi will be devised in the longer term. It is intended that standardised methodology will be the major output of such research equivalent to those that exist for bacteria.