A restaurant in Spain with a Michelin star has reopened almost one month after being linked to the death of a diner and 30 cases of food poisoning.

The Ministry of Health of Valencia detected the cases of food poisoning between Feb. 13 and 16 among customers of RiFF restaurant in Valencia.

More than 100 people who dined at the restaurant between these dates have been interviewed to try and find the vehicle of infection and food samples were sent to the National Toxicology Institute to be analyzed.

Initial investigations and inspections found the restaurant complied with sanitary regulations. It specializes in European cuisine and Mediterranean food. RiFF was opened in September 2001 and achieved a Michelin star in 2009.

Clinical symptoms of most cases were mild and involved vomiting and diarrhea. Spanish media reported a 46-year-old woman died.

In a statement, restaurant owner Bernd H. Knöller expressed his regret at the incident and said he was cooperating with authorities.

Knöller made the decision to close the restaurant until the causes of what happened were established and the Ministry of Health concluded its investigation.

Spanish media reported mushrooms bought from China could be responsible. Responding to these claims, Knöller said morel mushrooms were bought from an authorized distributor in León, Spain and not from China.

“In addition, the technical specifications coming with the product the supplier sent us did not specify the provenance. Importing from another country products that can be found in Spain is not part of RiFF’s philosophy or policy. With regards the cases of mild poisoning, I wish to add that the health authorities have, for the moment, not found a cause. We do not know whether it was the morels or another product,” said Knöller on Twitter.

“The restaurant has passed two health inspections. The second, and most recent of the two, was in response to a request from us. I wanted to be 100 percent certain (though I have realised that no restaurant can absolutely guarantee 100 percent safety). The health authorities have assured us at all times, since the first inspection, that there is no reason for the restaurant to remain closed.”

Knöller added it would be including a critical control point protocol for all aspects related with the restaurant and the death of the woman was still under investigation with no direct connection to the restaurant.

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