Staff at the Department of Health collected 275 food samples from two fresh markets and three weekly markets in Muang Nakhon Sawan, Tha Tako and Chumsaeng districts. Of the samples, 102, or 37%, contained formalin. At big, urban markets, formalin was found in as many as 59% of collected samples.
Contaminated foods included shrimp, squid, chopped ginger, chopped finger root, straw mushrooms, grey oyster mushrooms, black mushrooms, long beans and oak-leaf ferns.