Retailers urged to check whether packets are undamaged

China is toughening its examination of milk powder imported from New Zealand, according to the quality control watchdog, after revelations emerged on Tuesday of a criminal threat to contaminate some products with an agricultural poison.

The government has already taken steps and will demand each batch of milk powder imported from New Zealand have an official certificate telling that it does not contain the substance, sodium monofluoroacetate, or 1080, the General Administration of Quality Supervision, Inspection and Quarantine said in a statement.