World bivalve molluscs production (capture + aquaculture) has been increasing substantially in the last fifty years, going from nearly one million tonnes in 1950 to about 15 million tonnes in 2012. Being filter feeders, bivalves utilise natural plankton and detritus as feed and do not require artificial feeds. But this filter feeding nature is also the reason for the requirement of strict environmental hygiene to produce bivalves safe for human consumption. They tend to concentrate microorganisms, toxins and chemicals from the environment and therefore, their safety management requires stringent sanitary measures to ensure consumer protection. Following the request of Codex Committee on Fish and Fishery Products (CCFFP), FAO/WHO agreed to develop a technical document on the subject of Toxicity Equivalency Factors (TEFs) for marine biotoxins. This document is of high importance for food safety managers in member countries of both FAO and WHO.