Health officials visit a worker at the hospital. All the workers recovered and were released by the following day. — Photo baonghean.vn

NGHỆ AN — Health authorities in the central province Nghệ An are investigating a mass food poisoning incident that sent more than 70 workers to hospital after they had lunch on May 28.

The workers, employed by MLB Tenergy CO LTD in Yên Thành District, complained of nausea, vomiting and headaches after a meal at the company's cafeteria. They were rushed to local hospitals but all were released by the following day.

Investigators said tests revealed high histamine levels (739mg/kg) in the fried silver carps served at the cafeteria.

Investigators also found problems with the cafeteria's hygiene standards, including a lack of proper lids on rubbish bins, dirty food preparation areas and non-compliant food sample storage.

The authorities said a council of food safety experts will be convened to assess the test results and determine the specific cause of the incident.

Histamine is a chemical that can build up in fish if not stored properly. Histamine poisoning usually causes unpleasant but short-lived symptoms. — VNS