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Pesticide Residues Detected in Food After the Enactment of Cap 132 CM

Pesticide Residues Detected in Food After the Enactment of Cap 132 CM


(CMA Testing and Certification Laboratories)

The Pesticide Residues in Food Regulation (Cap. 132 CM) came into effect on 1st August last year. Since then the Centre for Food Safety (CFS) has taken over 11,000 food samples at import, wholesale and retail levels for pesticide residue testing. When the CFS finds excessive pesticide residues in food samples (i.e. exceeding the maximum residue limits (MRLs) / extraneous maximum residue limits (EMRLs)), she would issue a press release to announce the unsatisfactory results.

After reviewing all the relevant press release issued between 1st August 2014 and 19th January 2015, I have summarized problematic food commodities and the associated pesticides into tables, and conducted a detailed data analysis as below.

I. Problematic Food Commodities Found

In total, there were 16 types of food commodities with detected levels of pesticide residues exceeding the MRLs / EMRLs. White string pod is the food commodity with the greatest number of detected pesticides residues. A total of 4 different pesticide residues including “acephate”, “carbofuran”, “chlorpyrifos” and “methamidophos, was detected.

Chinese Lettuce was another food commodity containing a high number of detected pesticide residues, of which 3 different kinds of pesticides “methomyl”, “methamidophos” and “dimethoate” were found. Other food commodities including baby shanghai greens, chayote, Chinese white cabbage, Chinese wolfberry leaf, choi sum, grapefruit, green string pod, orange (including peel), pear, purslane, radish, radish shoot (including leaves and root), small Chinese white cabbage, water spinach and watercress, were usually associated with 1 to 2 kinds of pesticide residues.

II. Pesticide Residues Found

In total, there were 13 types of pesticide residues detected. Chlorpyrifos was the most widely present pesticide and associated with 5 different types of food commodities (including choi sum, water spinach, watercress, Chinese white cabbage and white string pod). For example, its highest level in choi sum exceeded the legal tolerance level i.e. MRL by 7.6-fold.

Residues of Carbofuran, Methamidophos, Cypermethrin and Dimethoate are also commonly detected in food. For example, the pesticide residue levels of carbofuran in green string pod, methamidophos in chayote, cypermethrin in Chinese wolfberry leaf and dimethoate in purslane exceeded their legal tolerance levels by 44-fold, 12-fold, 4.4-fold and 5.2-fold respectively.

Other pesticides including acephate, acetamiprid, cyhalothrin, dichlorvos, methomyl, profenosfos, thiabendazole and triazophos are associated with 1 to 2 different types of food commodities only.

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III. Prioritize the Test Items in a Pesticide Residue Monitoring Plan

Pesticide residue is a key issue in food safety for consumers and its monitoring is not only concerned by the government. Other stakeholders along the food chain including farmers, food importers, food manufacturers, food wholesalers and food retailers have the food safety responsibilities and are also required to formulate their own pesticide residue monitoring plans, in order to assure the foods they produce, manufacture, import and sell, comply with the legal requirements and are fit for human consumption.

Under the new legal requirement, tolerable residue levels for a significant number of pesticides are applicable for different foods. For example, over 80 pesticides with MRLs/EMRLs are set for the food commodity “Pome Fruits”.

Under the constraints of limited resources, the food trade of course cannot test foods for all applicable pesticides with MRLs/EMRLs. From the perspective of food safety risk, it is also not justified to check the levels of all applicable pesticides every time. Therefore, the food trade really wants to know which pesticide is more likely present in a specified food i.e. which pesticide is more risky to be detected. This helps them to determine the testing frequency of a “high risk” pesticide and a “low risk” pesticide for a particular food.

Table 1 and Table 2 highlight the prevalence of pesticide residues in different problematic foods sold in Hong Kong. They are essential for the local food trade to design a risk-based and feasible plan for pesticide residue monitoring. Indeed there are several other factors that we need to consider when we establish a meaningful testing plan. I will talk about those factors in the next article.