THE oyster industry insisted its shellfish are safe to eat after a national study showing more than three-quarters contain a bug.

Mersea fishermen defended their world-famous oysters in the wake of research by the Food Standards Agency.

Scientists discovered traces of norovirus in 76 per cent of samples tested from 39 farms across the UK.

Graham Larkin, operations manager for Colchester Oyster Fishery, said: “Everything has a trace of some bacteria or virus.

“As long as it’s below a quantifiable level, then it’s safe.

“The research showed 52 per cent were below the quantifiable level, so it’s not 76 per cent which are contaminated – it’s a much smaller amount.

“If you took this at face value, it’s like Edwina Currie and the egg, which ruined a lot of small farmers.

“It’s all out of proportion and it doesn’t take into account what the oyster industry is doing to combat the problem by testing.

“It has to be put into perspective .

“We sold hundreds of thousands of oysters this year and we have had three reported cases where people have been ill. That’s a very small percentage.”

Chris Avila, head chef and co-owner of West Mersea Oyster Bar, in Coast Road, said: “I don’t think hard and fast oyster eaters will be too fazed by this, as they know the ins and outs of what they are eating.

“Where I do think it will have a massive effect will be on people who are thinking about trying oysters, or who eat oysters on the odd occasion.

“A lot of those people, on hearing these reports, could be put right off.

“The biggest issue with this is that an average person may think if I eat this, I have a 70 per cent chance of getting ill – and that just isn’t true.

“We sold 80,000 oysters in the last year and we had one report of a problem.”

Scientists took samples from oyster farms across England, Scotland and Wales between September 2008 and August 2011.

Low levels of the virus, which causes vomiting and diarrhoea, were found in 52 per cent of the positive samples, according to the data.

The Food Standards Agency said it was difficult to assess the potential health impact of the findings because researchers were unable to distinguish between infectious and non-infectious norovirus in the shellfish.

The results of the study will form part of advice provided to the European Commission on what a safe level for norovirus in oysters should be.

A safe limit for the virus, commonly known as the winter vomiting bug, has not been established.

Andrew Wadge, chief scientist at the Food Standards Agency, said: “This research is the first of its kind in the UK.

“It will be important to help improve the knowledge of the levels of norovirus found in shellfish at production sites.”