Reports from Hebei, China say cabbage is being soaked in a carcinogenic preservative to keep it fresh, and it may be reaching Taiwan by way of forged Vietnamese certificates of origin — bad news for consumers and local vegetable farmers alike.

• Chinese buyers are soaking napa cabbage in formaldehyde solution, a Group 1 carcinogen, to preserve it; ingesting it at high concentrations can burn the stomach and intestines.
• Taiwan bans imports of fresh Chinese cabbage, but a forged Vietnamese certificate of origin costing a little over NT$10,000 can yield a price margin of NT$200,000 to NT$300,000.
• Taiwan's imports of cabbage and napa cabbage from Vietnam have surged nearly fivefold in recent years, while domestic cabbage arrivals have been low and prices have nonetheless fallen below NT$10 per kilogram — seen as an abnormal signal.
• Four months ago the Ministry of Agriculture pledged to establish a place-of-origin comparison database and isotope identification, but no concrete progress is visible so far.
• Wu Hsin-tai, a Taiwan Statebuilding Party candidate for city councillor, has called for a higher sampling-inspection rate, the addition of formaldehyde to targeted testing programmes, and an audit of processed products such as kimchi, pickled goods and frozen cabbage.

Outlook: The pressure falls on the Ministry of Agriculture and the Food and Drug Administration, and the question now is whether they will release sampling-inspection data and add formaldehyde to their testing list.