Research Highlight

From seafood to salads

Subhra Priyadarshini

doi:10.1038/nindia.2008.227 Published online 17 June 2008

The ice used to preserve seafood could contaminate other foods.

© Punchstock

Contaminated water used to keep seafood fresh during transportation could be a major source of the deadly bug Listeria monocytogenes that triggers off the food-borne disease listeriosis. A new study suggests1 that there is a risk of acquiring listeriosis through seafood in India, as raw seafood contaminates cooked food in many restaurant kitchens.

The study on seafood in the beach tourist resort of Goa found that though raw or semi-raw seafood is not generally consumed and L. monocytogenes is killed during cooking, it poses a health risk in kitchens where raw seafood contaminates already cooked or ready-to-eat food.

During the study, nine per cent of the tropical seafood samples were found to harbour L. monocytogenes, even though earlier reports had suggested the absence of the bug in tropical fish. The overall prevalence of L. monocytogenes in European raw fish was around three per cent. L. monocytogenes is commonly isolated from coastal waters and lake surfaces. Thus, ice made out of contaminated water and used to keep seafood fresh during transportation is a potential source of L. monocytogenes, says one of the researchers Vishal Parihar.

"In kitchens, raw food contact surfaces should not be used without careful cleaning when preparing ready-to-eat food such a salads and fruits. At the retail level, hygienic practices should be employed to reduce contamination of seafood with L. monocytogenes," he says.

Immuno-compromised individuals such as pregnant women, diabetics and elderly people are particularly susceptible to this organism. The most common manifestations are meningoencephalitis, septicaemia and abortion.

The study recommended education in food hygiene for retailers and consumers.

The authors of this work are from: ICAR Research Complex for Goa, Ela, Old Goa, India and Department of Restaurant and Culinary Arts, Örebro University, SE-701 82 Örebro, Sweden.


  1. Parihar, V. S. et al. Isolation and characterization of Listeria species from tropical seafoods. Food Control 19, 566–569 (2008)