Risk in Brief - Pesticide Residues in Food


  1. Pesticides are commonly applied to control pests in buildings, as well as in agricultural production to improve yield and quality. Pesticides may be applied to food or fodder crops to control pests, as plant growth regulator, defoliant, desiccant, fruit thinning agent or sprouting inhibitor. It may also be applied to animals to control external parasites.
  2. Pesticide residues in food may be resulted from direct use of pesticides on the food crop, animal feeding on pesticide-contaminated feed and/or environmental contamination.

Safety and Public Health Significance

  1. Depending on the nature of individual pesticide, the amount and duration of exposure, pesticides exceeding safety limits may cause acute and/or chronic effects in humans. Adverse health effects include damage to nervous system or other organs such as the liver and kidneys. Some may be transferred via the placenta or breast feeding, thereby affecting the foetal development.
  2. While acute toxicity is unlikely nowadays, the Joint Food and Agriculture Organization (FAO) and World Health Organization (WHO) Meeting on Pesticide Residues (JMPR)* is responsible for evaluating the safety of pesticide and estimating safety references like Acceptable Daily Intake (ADI) for estimation of chronic toxicity and Acute Reference Dose (ARfD) for estimation of acute toxicity.
  3. Since ADI related to chronic toxicity, it should be noted that dietary intake above the ADI occasionally does not automatically mean that health is at risk. Transient excursion above the ADI would have no health consequences provided that the average intake over long period is not exceeded as the emphasis of ADI is a lifetime exposure.

Maximum Residue Levels (MRL) of Pesticides in Food

  1. To protect the health of the consumers and at the same time facilitate international trade, based on data available, the Codex Alimentarius Commission (Codex) established Maximum Residue Limits (MRLs) for individual pesticide in selected commodities according to Good Agricultural Practice (GAP). The ultimate aim is to use the least possible amount of pesticides for the desired function, while keeping the exposure level below the safety reference value.

Local Regulatory Control

  1. With effect from 1 August 2014, the Pesticide Residues in Food Regulation (Cap 132CM) came into force. The Regulation specifies in Schedule 1 a list of MRLs/EMRLs for certain pesticide-food pairs, in which the levels of pesticide residues present are not permitted to exceed. For pesticide residues with no specified MRLs/EMRLs in Schedule 1, the Regulation stipulates that except for exempted pesticides, import or sale of food containing such pesticide residues is allowed if the consumption of the food concerned is not dangerous or prejudicial to health based on risk assessment conducted by CFS.
  2. The formulation of Schedule 1 to the Regulation was based primarily on the available standards recommended by Codex, supplemented by the available standards of the Mainland and other major food exporting countries to Hong Kong (including the United States and Thailand), taking into account comments received from stakeholders during public consultation.
  3. Under the food surveillance programme of CFS, samples of different foods are taken for analysis and verification of compliance with the MRL/ EMRL stipulated in Schedule 1. CFS will take appropriate follow up action to ensure the problem has been rectified at source before their reintroduction to the local market.

Advice to the Trade

  1. During the use of pesticide for crop protection, the farmers should follow GAP which include but not limited to the following recommendations –
    1. Use only permitted pesticides;
    2. Apply minimum quantities necessary to achieve adequate control;
    3. Leave residues that are the smallest amounts practical and that are toxicologically acceptable;
    4. Strictly adhere to the withholding period or pre-harvest interval specified on the label of the pesticide to avoid causing harvested crops to contain excessive pesticide residues.
  2. For more information regarding the list of permitted pesticides in Hong Kong as well as the safe use of agricultural pesticides, please visit the Agriculture, Fisheries and Conversation Department's Website at http://www.afcd.gov.hk/english/quarantine/qua_pesticide/qua_pesticide.html.

Advice to the Public

  1. Vegetables are an essential component of a healthy and balanced diet. Members of the public are also advised to maintain a healthy and balanced diet as a part of a healthy lifestyle.
  2. Vegetables should be washed thoroughly in clean running water before cooking and consumption. When appropriate, scrub produces with hard surfaces with a clean produce brush to remove dirt and substances, including pesticide residues and contaminants, from the surface and crevices. CFS no longer recommends soaking or blanching in preparing vegetables due to the loss of nutrients during the process, low incidence and levels of pesticide residues detected in foods and lack of confirmed pesticide-related food poisoning cases as recorded by CHP in recent years. This advice has been endorsed by the Expert Committee on Food Safety of the CFS.
  3. Use of soaps, special detergents or produce washes is not recommended.
  4. Even though some pesticide residues may be transferred to the infant via human milk, WHO considers that breastfeeding is an unequalled way of providing ideal food for the healthy growth and development of infants; it also contributes to the health and well-beings of mothers.

Risk Assessment Section
Centre for Food Safety
March 2017

* JMPR is the abbreviated title for the Joint Meeting of the FAO Panel of Experts on Pesticide Residues in Food and the Environment and the WHO Core Assessment Group. The FAO Panel of Experts is responsible for reviewing residue and analytical aspects of the pesticides considered, estimating the maximum residue levels according to supervised trials and GAP. The WHO Core Assessment Group is responsible for reviewing toxicological data on the pesticides, estimating safety reference (i.e. acceptable daily intake) and levels of dietary intakes of pesticide residues. As necessary, acute reference doses for pesticides are estimated along with appropriate estimates of short-term dietary intake.