Families: 'Is it safe for us to tuck into fresh seafood in Venice?'

Q. We have booked a city break in Venice for our family and are looking forward to tucking into fresh seafood.

Q. We have booked a city break in Venice for our family and are looking forward to tucking into fresh seafood. However, friends have warned us that the pollution of the lagoon can enter the food chain and so we should be careful about what we eat. How can we safeguard against this?
Mrs S Higgins, via e-mail

A. Fresh seafood is, of course, a treat, but there are some precautions that you should bear in mind. Seafood is very much part of the Italian diet - restaurants often offer a large bowl of seafood salad containing squid, clams and other shellfish as a starter. Sea urchins, mussels, and even razor shells are also served raw, especially in the southern Adriatic, and local supermarkets occasionally have a tank of live lobsters and eels for customers to choose from.

Despite being seafood lovers, most Italians wouldn't, however, eat it more than 5km from the sea. People who live in Rome, for example, would drive to the coast to a fish restaurant but wouldn't risk it on the eastern side of the capital.

Seafood is likely to be unsafe unless it is fresh and has come from clean water. The sea has a tremendous capacity for cleaning itself, especially if any polluted area is regularly and thoroughly mixed and flushed with unpolluted waters. The whole of the Mediterranean suffers from being overused as a waste-disposal unit, though, and that capacity to self-clean is under stress; lagoons and narrow-necked bays are the worst off, especially if sewers discharge into them. The problem is that it is difficult to be sure about the origins of your meal. I would certainly hope that creatures that have lived in the Venice lagoon wouldn't arrive on your plate.

Italians are very health conscious - not least because there has been a cholera epidemic in Naples within living memory. Clearly you will be reassured if you have seen your supper swimming around in a tank of water before it is taken off into the kitchen, but many children (and some adults) are upset at interacting with their meal before it is cooked.

Many sea creatures feed by filtering minute particles of food and other detritus out of their watery environment, and this filtration process tends to concentrate pollutants, including bacteria of unsavoury origins. Gourmets will not welcome a description of exactly what shellfish collect, but, suffice to say, the accumulation can lead to food poisoning in a variety of forms, and filter-feeding shellfish are the most likely source of problems. Diseases including cholera and hepatitis A can be acquired from raw or lightly cooked shellfish.

Fortunately, however, proper cooking kills most of the microbes that cause gastroenteritis; and cholera and hepatitis are destroyed by boiling for just 60 seconds. Even so, consider being immunised against hepatitis A; it is a good vaccine that gives 10 years' cover and is available on the NHS from your GP.

Simple gastroenteritis is a bother but usually settles within 48 hours (Dioralyte or other oral rehydration salts are worth packing), but with increasing pollution of the seas there are more cases of poisoning from shellfish toxins. The most bizarre is called ciguatera. In common with many shellfish-associated poisonings, its symptoms usually start with vomiting, watery diarrhoea and abdominal cramps, but these settle within 24-48 hours.

Drinking plenty of clear fluids is the treatment at this stage and, especially if the victim is a child, oral rehydration salts are probably the best solution.

In addition to these early symptoms, ciguatera also causes some strange sensations, including numbness and tingling of the lips and extremities, tooth pain or a sensation of loose teeth and, weirdest of all, a reversal of sensation in which cold objects burn when touched and hot objects feel cold. Most cases of ciguatera were first reported in the Tropics and the symptoms were so bizarre that victims were diagnosed as malingerers; sufferers must have been upset at being classified thus since symptoms can persist for many weeks. The best treatment is prevention; the toxin is accumulated in the viscera of fish and is more likely in large fish (more than 2.5kg) and in fish caught during red tides or other freak maritime events. Ensure that yours look fresh before cooking if you can.

Finally, it is worth highlighting that many unfamiliar kinds of fish are on offer in restaurants in Italy and they usually contain lots of bones; these can trouble children if they are used to bone-free fish fingers.

Dr Jane Wilson-Howarth is co-author of 'Your Child Abroad: A Travel Health Guide' (Bradt). She works as a GP and at a travel clinic, www.travelcliniccambridge.co.uk