For the purpose of this document the term microbiological hazard includes hazards caused by bacteria, viruses, yeasts, moulds, algae, parasitic protozoa, their toxins and metabolites. All available scientific data relevant to the risk assessment should be considered. These data are likely to come from different sources. For example, data may include clinical and epidemiological studies such as disease symptoms, severity and dose-response data; microbiological studies including the physiology, biochemistry and ecology of microorganisms and the biochemistry and stability of their toxins; sources and prevalence of microorganisms and their toxins in foods and the effect of processing and food handling operations on them; data on food production and consumption patterns. Where scientific data are limited, otherwise incomplete or conflicting, informed judgements may be made on the basis of the best information available.
