ISO 6887-3:2003 specifies rules for the preparation of fish and fishery product samples and their suspension for microbiological examination when the samples require a different preparation from the method described in ISO 6887-1. ISO 6887-1 defines the general rules for the preparation of the initial suspension and decimal dilutions for microbiological examination.

ISO 6887-3:2003 only describes methods of preparation that are applicable to several microorganisms simultaneously. It excludes the preparations that only apply to the detection and/or enumeration of a single microorganism where the methods of preparation are described in the relevant standard concerning that microorganism, for example Vibrio parahaemolyticus.

ISO 6887-3:2003 is applicable to the following raw, processed, cooked or frozen fish and shellfish and their products: raw fish, crustaceans, molluscs and others; processed fish, crustaceans, molluscs and others; frozen fish, crustaceans, molluscs and others, in blocks or otherwise.