A man suspected of contaminating food with rat poison at a supermarket in Guangzhou's Haizhu district, including rice, fish and meat, has been arrested, Guangzhou Daily reported, citing Tuesday's notice by the district government.

Trust-Mart workers wait for customers to return food, which was purchased on Jan 3 and Jan 4 and thought to be contaminated with rat poison, in Haizhu district, Guangzhou, South China's Guangdong province. [Photo/Guangzhou Daily]

The 21-year-old suspect, surnamed Zhang from Guangdong's Maoming city, called the Trust-Mart supermarket about 9:00 pm on Jan 3, reportedly asking for ransom, and called again the next afternoon saying he had poisoned six kinds of food there.

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The food was sealed immediately and found to be contaminated with rat poison after a police investigation.

A total of 686.3 kilograms of rice were sealed. In addition, 363.5 kg of rice, 4.54 kg of fish and 1.95 kg of meat, 3.03 kg of mushrooms, 1.54 kg of silk noodles, and 5.64 kg of glass noodles, thought to be contaminated, were sold.

Local hospitals were ordered to monitor the situation, but no suspected rat poisoning cases were reported.