Dongguan authorities have launched an investigation into the mass food poisoning of workers in Guangdong province, food and drug administration sources said on Thursday.

Food samples are being examined, and the administration has promised to make the findings public, the sources added.

The probe was launched after 160 members of staff from Hsu Fu Chi Food Co. Ltd took ill after eating snacks at the company's canteen on Tuesday.

One worker died in her dormitory the next day. But Hsu Fu Chi said it had not confirmed that the worker died of food poisoning.

Police have also launched an investigation.

About 40 workers were still in hospital on Wednesday night.

Most of the victims thought they had eaten contaminated food from the company's canteen which is contracted outside the company.

And on Monday, 116 staff from a Korea-funded electronic company in Dongguan's Liaobu township also said they suspected they had eaten contaminated food.

Contact the writer at zhengcaixiong@chinadaily.com.cn