Listeria innocua and Salmonella panama in estuarine water and seawater: a comparative study

This study was conducted to collect information on the behavior of Listeria spp. in estuarine water and seawater. Listeria innocua was inoculated in water microcosms, in parallel with Salmonella panama, with the aim to obtain comparative data with this more well-known pathogen. In every situation L. innocua exhibited a more rapid die-off than S. panama, with decimal reduction times always shorter than those observed for S. panama. For both bacterial strains the decimal reduction times were shorter in seawater than in estuarine water and shorter at 18°C than at 5°C. In seawater, as in estuarine water, bacterial die-off was more rapid in natural water than in sterilized water. These data obtained from a conventional approach, on culturable bacteria show the high sensitivity of Listeria in water. However, the survival is long enough for bioaccumulation by shellfish in polluted coastal waters.