| Resumo: |
After a general presentation of the Thau lagoon together with its geographic location, socio-economic activities linked to shellfish culture and fishing, this paper investigates the health conditions of the shellfish harvesting areas. I he influence of heavy rainfall following a prolonged drought period is underlined as a determining factor of the momentary bacterial pollution in the harvesting areas, leading to a suspension of sales based on analyses relying solely on the detection of faecal coliforms. As of 1989, bacteriological monitoring was reorganized in the form of a data collection network taking into consideration environmental assessments of water quality as well as shellfish hygiene in order to protect consumer health. Its extension to the Languedoc lagoons and to the Thau lagoon in particular required an adaptation of the general principles of coastal monitoring implemented by IFREMER along the entire French coastline. In this perspective, the search for Salmonella is performed only in case of excessively high contamination. A bacterial pollution was observed during the month of November 1989 with detection ofSalmonella. An analysis of the results underlines the lack of correlation between faecal coliforms and Salmonella (nearly continuous presence of Salmonella in shellfish while faecal coliforms progressively disappear). This observation remained valid throughout the period between December 15 and January 3 over which the public authorities conducted an intensive and almost daily monitoring of the harvesting areas. The costly intensive monitoring performed by the laboratories did not really provide a satisfactory approach to cover the public health risk. Marketing of the shellfish was authorized only after negative results were obtained, corresponding to normal monitoring conditions. An analysis of the epidemiological surveys conducted by the services of the Ministry of Health failed to provide evidence of any correlation between the observed shellfish contamination and consumer morbidity. Beyond the health benefits presented by Salmonella analyses, it is appropriate to raise the problem of the interpretation of their results, particularly in cases when this criterion can be used within a regulatory framework.
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