The Department of Science Services has advised consumers that paper-wrapped fried chicken may be contaminated with carcinogenic substances from the wrapping paper.

Responding to a report on social media, Dr. Kanit Tapasa, spokesman for the department, explained that there are currently two types of pulp used in the production of paper, pure natural pulp and recycled pulp.

In the production process of pure paper pulp, he said that chemicals, such as sodium hydroxide and chlorine, are used to produce white pulp, adding that most of these chemicals are eliminated during the washing process, but heavy metals may remain in the pulp, left by water or engine oil used in the production process.

Pulp which comes from recycled paper has gone through a process to separate foreign matter from the paper and the de-inking process may leave residues of toxic substances.

When chicken, which is wrapped in the paper, has been fried in boiling oil, the heat from the oil may cause heavy metal residues in the paper, such as lead, cadmium or mercury, to be released into the chicken, even though the paper may be heat resistant and will only catch fire in heat of about 222^oC, while the temperature of boiling oil is about 190^oC, said Dr. Kanit.

He advised consumers to ask the fried chicken vendor whether the paper they use to wrap the chicken is cooking paper or paper suitable for contact with hot food.