Beneath the gloomy seas off southern England, 400 million mussels encrust ropes hanging from buoys dotted over an area the size of the country's biggest airport.
Almost 5 km (3 miles) from shore at its nearest point, Europe's largest offshore mussel farm was built by the Holmyard family in Lyme Bay, where they believed it would be free of the millions of gallons of sewage pumped into U.K. waters each year.
But even this far offshore, harmful bacteria such as E.coli can pollute the water, blocking exports to continental Europe for weeks and damaging the prospects of a business producing sustainable food.
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