All mussels from the islands of Shetland have been withdrawn from sale and disposed of after the Food Standards Agency (FSA) found dangerously high levels of toxins in the produce.
Harvesting areas in the north and west of the islands have been affected, with 11 sites compulsorily shut down by the Council and all other areas voluntarily closed as a result.
The FSA, which monitors levels on a weekly basis, explained that the toxins are produced by marine phytoplankton and naturally-occurring algal blooms, with levels increasing to unprecedented levels in recent summer months.
Shetland Mussels managing director Michael Tait told the BBC: "This is the first time that we have experienced a problem with customer illness in our 16 years of production.
"Shetland Mussels is SALSA (Safe And Local Supplier Approved) approved with full traceability, which has allowed us to isolate the affected batches, and this system has worked well in this situation."
He confirmed that they had contacted all businesses affected to ensure that any remaining produce had been destroyed.
This is the second bout of poisoning originating in Scottish waters in past weeks, with a shellfish toxin warning issued in Fife late last month.
Seafood Shetland said that a full investigation into the toxin levels is taking place, while the FSA has stated that no further risk to customers remains.