A fruit and vegetable survey, released by the Thai-Pesticide Alert Network (Thai-Pan) late last week to widespread public concern, is questionable, says the National Bureau of Agricultural Commodity and Food Standards (ACFS).
Dujduan Sasanawin, the ACFS secretary-general, said Monday the survey sample sizes were too small, which would affect the results. The results didn't accurately reflect nationwide data, she said.
She said she was speaking to calm public fears about the survey, which raised concerns about the extent to which readily-consumed fruit and vegetables are contaminated. At least 60 samples should be tested for each category of fruit and vegetables to come to any valid conclusions, Ms Dujduan said, adding three to four samples is not good enough.
Thai-Pan's survey was drawn from a test carried out by a lab in the United Kingdom which analysed 138 samples of popular fruit and vegetables randomly collected from supermarkets in greater Bangkok, Chiang Mai and Ubon Ratchathani on March 16-18.
The results showed 46.6% of samples contained residue higher than the level of accepted safety standards. Notably, 57% of fruits and vegetables granted the "Q mark" for quality by the ACFS were found to have unsafe levels of contaminants.
About 25% of the products certified as organic products have been found to contain chemical residues exceeding acceptable standards.
The Department of Agriculture is responsible for checking and granting Good Agricultural Practice certification. Quoting an official at the department, Ms Dujduan said organic product certification procedures meet international standard requirements.
Meanwhile, Kingkorn Narintarakul Na Ayutdhaya, deputy director of BioThai, which is a member of Thai-PAN, has defended the survey results, insisting all 138 samples were sent to the lab with more than 450 types of substances detected.
According to the lab-test guidelines, each sample comprised 1kg of fruit or vegetables popular among Thais.
"Our survey is from a consumer perspective. It raises awareness [of chemicals used in farming products] among consumers," she said, urging authorities to reveal the in-depth practices employed to study the safety of farm produce.