China's food safety authorities ordered nationwide inspections of perishable vegetables on Sunday after reports that Chinese cabbage buyers in Hebei province used a formaldehyde solution to preserve the produce during transportation.

The State Council's Food Safety Office, the Ministry of Agriculture and Rural Affairs and the State Administration for Market Regulation said on Sunday night that they had immediately directed local authorities to investigate the case involving the tainted cabbage in Kangbao county of Hebei.

The statement came after a video posted online alleged that some agricultural produce buyers in Tunken township, Kangbao county, had dipped Chinese cabbage in a formaldehyde solution before loading it for transportation to better preserve it.

Some of the cabbage was reportedly destined for Suqian in Jiangsu province, while other batches were allegedly headed to a market in Hefei, Anhui province.

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The Kangbao county government confirmed on Saturday night that the practices shown in the video had occurred and described the use of formaldehyde for transport preservation as illegal.

Police have taken legal measures against the people and vehicles involved, while authorities launched a countywide inspection of vegetable production, purchasing, transportation and other links, the county government said. They are also tracing the distribution of the affected cabbage.

As of late Saturday, none of the batches of tainted cabbage had entered the Xinfadi market, one of Beijing's major sources of fresh produce, the Fengtai district in the capital said in a statement on Sunday.

The Xinfadi market said it has strict requirements for agricultural produce entering its trading area, including origin documentation and sampling tests. It has also increased the frequency of rapid testing for pesticide residues and illegal additives in vegetables following the incident.

It added that its cabbage supply remains sufficient. Cabbage prices at the market were stable and had not been affected by the incident as of Sunday. The market advised consumers to purchase vegetables through licensed supermarkets and wholesale markets and to consult market operators if they have concerns about the origin of produce.

Under China's Food Safety Law and Law on Quality and Safety of Agricultural Products, formaldehyde cannot be used as a food-processing aid and adding formaldehyde to food in any manner is illegal.

Contact the writers at zhaoyimeng@chinadaily.com.cn