Is it Really a Food Safety Hazard? – Migration of Formaldehyde From PVC Tape to Vegetables Upon Tying Them


  The news media in Mainland China reported that excessive formaldehyde has been detected in the PVC tape used for tying vegetables on sale in the market. The migration of formaldehyde from the tape to vegetables through their contact surface is hazardous to human health since consumption of formaldehyde-contaminated vegetables over extended period of time may result in cancer.


  Food contact materials refer to materials used for food packaging, with common types such as PVC, adhesive tape, metal, paper and printing ink, etc. The migration amount for assessing the “migratability of packing materials” depends on factors such as food type, constituent compounds of the packing material, storage temperature, food contact surface area and the duration of contact. In addition, chemical toxicity testing and studies on risk exposure and analysis are also taken into consideration. So far, there are no scientific data showing that the disposable PVC tape causes excessive formaldehyde in vegetables upon using it to tie vegetables and that long-term consumption of these vegetables leads to cancer or poisoning.


  The PVC tape often used for tying vegetables contains non-food grade substances, including formaldehyde, phthalates (used as plasticisers) and heavy metal. Since the constituents of the tape remain rather stable at room temperature, the possibility of formaldehyde release by their degradation is very low. The water-soluble formaldehyde residues in vegetables can be reduced by proper washing, soaking and thorough cooking of the vegetables. Moreover, phthalates are fat-soluble chemicals which may migrate to the food in contact with them only at a higher temperature (above 60) and over a long duration of time. Apparently, as the contact surface between the PVC tape and vegetables is limited, with the contact temperature not high and the storage time not long, the risk of migration of substances from the tape to the vegetables is relatively low.


Advice to the trade:

  1. Avoid exposure of PVC tape used for tying vegetables to direct sunlight since they may release harmful substances upon exposure to heat.
  2. Though formaldehyde is harmful to human health, it is sprayed on vegetables as preservatives to increase their shelf life. Anyone who applies formaldehyde to food intended for human consumption may have violated the “Food Safety Law” and IAM shall take necessary actions in accordance with the law.


Advice to the public:

  1. Before washing the vegetables, the PVC tape used for tying them must be removed to prevent contamination by heavy metal contained in the printing ink on the tape and other released chemicals.
  2. Wash and soak vegetables thoroughly with clean running water. Allow vegetables to soak for 10 to 15 minutes for two to three times.
  3. Blanch the cleaned vegetables to reduce pesticide residues in them.
  4. Never cook vegetables with their PVC tape on them to prevent it from releasing harmful substances.