Over 100,000 salted duck eggs and two tonnes of an industrial salt used to preserve them have been seized in China after it was found the salt could cause cancer.
Police and quality supervision officials raided an underground salted egg production site in Jiangmen city of Guangdong province, the Shanghai Daily reported.
The industrial salt was found to contain nitrite, the long-term intake of which can lead to cancer, according to the Southern Metropolis Daily.
Officials said they were searching for eggs on sale but admitted it was an uphill task as they are sold in bulk without brands and batch numbers.
The seized salt and eggs were worth 57,000 yuan (around $9,000).
The boss of the production plant and two workers were arrested. Together they produced more than 3,000 salted eggs a day.
The plant used industrial salt as its price is 500-800 yuan per tonne, while edible salt costs about 1,000 yuan.
Salted duck egg is a traditional Chinese food made by soaking duck eggs in brine, or packing each egg in damp, salted charcoal. It is a popular food in summer, when the weather is hot and many people have a poor appetite.