FDA’s testing method disputed

GOSSYPOL?:Lawmakers and experts questioned the method used to test Chang Chi’s cooking oil and demanded zero tolerance for the chemical

By Alison Hsiao  /  Staff reporter

Sat, Nov 02, 2013 - Page 4

Lawmakers and chemistry and public health experts yesterday questioned the results of the Food and Drug Administration’s (FDA) tests for gossypol pigment content in Chang Chi Foodstuff Factory Co’s cottonseed oil.

Democratic Progressive Party legislators Tien Chiu-chin (田秋堇) and Chen Chi-mai (陳其邁) questioned the optimality of the FDA’s testing method, asking for clarification on whether gossypol was detected, or whether the agency was not capable of conducting a comprehensive examination.

Gossypol is a major pigment in cottonseed and cotton plant and excessive consumption can be harmful to human health.

Crude cottonseed oil that has not been refined also contains the substance.

“While HPLC [high-performance liquid chromatograph] determination of gossypol, which is how the agency has been conducting the test, has a testing limit of 1 part per million [ppm], that of LC/MS/MS [liquid chromatography/mass spectrometry/mass spectrometry] can be much lower,” Tien said.

She added that the FDA recently set the maximum residue limit (MRL) for gossypol at 1ppm “according to the limit of the testing method that the FDA has adopted,” but Tien and other lawmakers are asking for zero tolerance for gossypol residue in cottonseed oil, “not a maximum residue level that implies products with a gossypol content lower than that level are edible.”

She also accused the agency of failing to provide reports on how samples were collected from the companies and what they were, “as they would affect how convincing the testing results are.”

National Taiwan Normal University professor of chemistry Gaston Wu (吳家誠) added that cottonseed contains gossypol in two forms: free gossypol (toxic) and bound gossypol (non-toxic).

“Free gossypol, the toxic form, might not be detected in the testing process, but as to whether bound gossypol would be liberated after high-temperature cooking and human digestion is still unknown, so bound gossypol should also be included in the routine testing,” Wu said.

FDA official Shih Yang-chih (施養志) said that the agency had tested Chang Chi’s cottonseed oil, both crudely refined and refined, using the stricter testing method (LC/MS/MS) and a lower testing limit of 50 parts per billion (ppb), and found no gossypol content.

“However, validation of the method is still under way,” Shih said, adding that the method would be made public on the FDA Web site, as requested, alongside HPLC’s for manufacturers’ reference.

When asked if the new method would lead to a lower MRL, Shih said he does not make the decisions, but added that “the recently set MRL was set according to our testing limit.”