POLICE are probing seven employees of an Almeria-based company that allegedly sold 14,000 kilos of contaminated tuna.
It comes after at least 105 people across Spain and Europe fell ill after eating the toxic fish.
All suffered symptoms associated with histamine poisoning including an itchy throat, sweating, hot flushes, nausea, vomiting, and reddened skin.
Although tuna is naturally rich in histamine, poor hygiene during production and handling, particularly exposure to high temperatures, may lead to a dangerous spike which cannot be removed by cooking or freezing.
None of the suspects have yet been held, as detectives continue investigations which began in May when the scandal broke out.
Spanish consumers fell ill in Andalucia, Murcia, Valencia, Catalonia, Aragon, Castile y Leon, Madrid and the Basque Country, while a number of cases were also reported from Germany, France, Italy and Portugal.
Guardia Civil officers swooped on the premises operated by Garciden SL after the Junta de Andalucia regional council issued official health warnings and six batches of fresh tuna were removed from the market.
But they have been unable to trace the precise origin of the contaminated fish due to a lack of paperwork and hygiene records, sparking fraud accusations.
Labels attached to the packaging also suggested they had been line-caught when in fact a large bag-like net called a purse seine was used.