Eating more vegetables is good for health. However, it could have adverse effects if the vegetable is contaminated with excessive pesticide residues and heavy metals. The Consumer Council has conducted a comprehensive test for levels of over 300 pesticide residues and 7 heavy metals. 127 samples of vegetables were tested including "organic" produce.
75 of the 127 samples were claimed to be organic, of which 28 (37%) were found to contain pesticide residues.
The results showed that "organic" produce are not spared of food safety risks. One each of the "organic" purple sweet potatoes and carrots tested were found to contain pesticide residues exceeding the Maximum Residue Limit (MRL) or heavy metal at a level approaching the threshold.
The council has passed test results and sample lists to the Centre for Food Safety (CFS) for reference and to take follow up action on suspected cases of regulation contravention.
French beans and sweet potatoes contain excessive pesticide residue "chlorpyrifos"
1 French bean sample imported from the Mainland was found to contain chlorpyrifos at a level of 0.03 mg/kg exceeding the MRL of 0.01 mg. 1 sample of purple sweet potato with "Organic" printed on package, also imported from the Mainland, was found to contain chlorpyrifos at a level of 0.07 mg/kg, exceeding the MRL for sweet potato of 0.05 mg/kg.
French beans: the same French bean sample was also found to contain another 5 types of pesticide residues, including prochloraz at a level of 4.74 mg/kg. A 60 kg adult eating 80 g of the sample each time for 2 meals in a day would have taken in prochloraz above the Acceptable Daily Intake (ADI), posing damage to health for prolonged intake.
Flowering Chinese cabbages: 18 (86%) out of 21 samples of flowering Chinese cabbages were found to contain pesticide residues. Among which 8 (38%) were found to contain difenoconazole at a level ranging from 0.02 mg/kg to 0.14 mg/kg, still below the MRL (35 mg/kg).
Tomatoes: 11 (73%) out of 15 samples of tomatoes were found to contain pesticide residues and as many as 21 types of the pesticide residues were found in all. The most common one is dimethomorph which was found in 4 (27%) samples at a level ranging from 0.01 mg/kg to 0.04 mg/kg, but still below the MRL (1 mg/kg).
It must be pointed out that pesticide may have to be used in planting and crop storage in order to kill insect pests and fungus. However, the toxicity of different pesticides can be different. Inadvertent intake of a substantial amount of pesticides within a short time, such as by accident or in case of leakages, may cause symptoms of acute pesticide poisoning. In normal circumstances of vegetable consumption, it is unlikely to take in pesticide residues in such huge amount to cause poisoning with those symptoms of acute intoxication.
Flowering Chinese cabbage and organic carrot were found to contain heavy metal cadmium reaching upper limit
Cadmium was detected in a number of samples including 6 flowering Chinese cabbages, 5 potatoes, 2 carrots, 3 Chinese cabbages and 1 cabbage at various levels ranging from 0.02 mg/kg to 0.10 mg/kg. Although the cadmium level has not gone beyond the upper limit (0.1 mg/kg) defined in local food legislation, 1 flowering Chinese cabbage sample from the Mainland has just reached the threshold.
In another organic carrot sample imported from the US, 0.09 mg/kg of cadmium was found, which was almost reached the upper limit. Long-term consumption of cadmium-rich food may cause renal damages.
Organic white cabbage: an organic white cabbage sample was found to contain 0.06 mg/kg of lead, not exceeding the legal limit.
Less pesticide residues were found in 13 cabbage samples tested and amounts found were small.
Pesticide residues and heavy metals also found in Organic produce
Loose packs are obscurely displayed in retail shops
Consumers should also beware that pesticide residues or heavy metals were found in some organic produce such as sweet potatoes and carrots. Organic farming does not guarantee pesticide residues would not be present in produce. According to the organic agricultural law in the US, crops found to contain less than 5% of pesticide residues, a limit set by the US Environmental Protection Agency, can still be sold as "organic produce", provided that the presence of pesticide residues is the result of environmental contamination instead of intentional used by the farms.
Many pre-packaged organic vegetables carry on the package the word "organic" as well as logos or codes issued by the accrediting or certification institutions. However, shops selling "organic" vegetables in loose packs may only post in the shop a certificate issued to the supplying farm. Relevancy of the certificate to the vegetables in loose packs is not as distinct as those being labelled on prepackaged products. Consumers can only rely on the information given by shop operators in identifying the produce.
The Council alerted consumers to be cautious when purchasing loose pack organic vegetables. Before paying, they should ask for shop operator's confirmation and a receipt to state explicitly that the vegetable in question is "organic". In an event of dispute, evidence such as clearly stated sales receipt could facilitate redress pursuit.
The Council also calls on shops selling organic vegetables to print on the sales receipt that the vegetable sold is organic so as to boost consumer confidence.
A need to tighten regulatory control
Recent news reports pointed out that the limit of lead content in food is too loose in the local regulation. The Council agreed that there is room to tighten the limit. The Council suggests that the Government should refer to overseas regulations on heavy metals contents in foods and consider amending local regulations to enhance protection of food safety in Hong Kong.
Smart tips about consuming vegetables:
- Eat more dark green vegetables as well as vegetables in different colours;
- Select a variety of foods from different sources for a mix of nutrients and reduce the likelihood of excessive exposure to a single pesticide;
- Buy seasonal fruits and vegetables or buy from local farmers or markets with good reputation;
- Rinse fresh fruits and vegetables thoroughly under running water to remove dirt, bacteria and traces of chemicals from the surface of fruits and vegetables. Be mindful that not all pesticide residues can be removed by washing, though;
- Consumers can also peel fruits and vegetables, but peeling could mean losing some dietary fiber and nutrients;
- Before cooking, rinse and soak vegetables in water for one hour, or blanch them in boiling water for one minute and discard the water. This helps dilute pesticide residues and heavy metals.
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