Monitoring and control of pesticide residues in food within the European Union

What do we mean by a pesticide?

Stewart Reynolds, Senior Scientist, Food Quality and Safety Programme, Food and Environment Research Agency

Most people would think of pesticides as chemicals that are mainly used in farming to control common pests, such as insects (insecticides), moulds / fungi (fungicides) and weeds (herbicides). However, there are other chemicals that have other important uses in food production and food processing and also need to be regulated and monitored. These include ‘plant growth regulators’ that are used to beneficially modify plant growth processes, and ‘biocides’ that may be used as disinfectants to control unwanted microorganisms. Examples of recent issues specifically associated with residues arising from the use of plant growth regulators and biocides are discussed later in this article.

There are two main reasons that foods are analysed for pesticide residues. The first is to ensure that consumers are not being exposed to concentrations of pesticides that are harmful to health. The second is to ensure that concentrations of the pesticides do not exceed statutory maximum residue levels (MRLs).

Who is responsible for the controls?

European Standards are agreed centrally within the European Union. The European Food Safety Authority (EFSA)¹ is responsible for matters relating to risk assessment. Management of the risk is undertaken at a national level working to regulation and inspection. These requirements are established collectively by participating countries with the European Commission through the Directorate General for Health and Consumer Protection².

Each Member State is audited regularly by the Food and Veterinary Office (FVO)³, a service of the Commission. Through audits, inspections and related activities, the FVO checks that countries are fulfilling their obligations under the EU food safety and quality legislation. It also carries out regular audits / inspections in third countries that export commodities to the EU to check that the regulatory process is being properly implemented and enforced. The Commission, EFSA and the FVO work closely together and with the relevant competent authorities in each member state and in third countries.

There are two regulations that are particularly relevant:

• Regulation (EC) No 882/2004 of the European Parliament and of the Council⁴. This is an overarching regulation that ensures that official controls are performed to ensure that food and feed is safe and wholesome
• Regulation (EC) No 396/2005 of the European Parliament and of the Council⁵. This regulation is specific to pesticides residues in food and has set MRLs for pesticide residues in foods of fruit, vegetables, cereals and products of animal origin. It came into force in September 2007 and for the first time set harmonised MRLs across the whole of the EU. MRLs have been set for more than 150,000 pesticide / commodity combinations. Laboratory analyses of food samples in monitoring or enforcement programmes are conducted to establish if an MRL stipulated in this regulation has been exceeded.

The EU Multi-Annual Co-ordinated Control Programme

For many years countries organised their own monitoring programmes. The introduction of EU-harmonised MRL legislation was accompanied by the requirement to also take part in a coordinated programme. Initially this was only a voluntary commitment, but in 2009 it became mandatory for all member states to participate in this programme, which is now known as the ‘Multi-Annual Co-ordinated Control Programme’ (MACCP).

Within this co-ordinated programme, the current plan is for 2013, 2014 and 2015⁶ and specifies 30 to 40 different foods that are the major components of the diet in the EU. Since pesticide usage usually changes every few years, it is a requirement that pesticide residues in these staple items of food should be monitored over a three-year cycle. The numbers of samples to be taken and analysed are apportioned among Member States (MS) according to population statistics. The total minimum number of samples per commodity for the whole programme is 642, which allows a 99 per cent detection rate of samples with residues, at or above, the limit of determination (LOD), provided not less than one per cent contain residue levels ≥LOD. For the highest population country, Germany, the minimum number of samples for each food is 66, whereas for much smaller countries, such as Malta, the minimum number is only 17. A total of 190 different pesticides are targeted for fruits, vegetables and cereals whereas for products of animal origin 65 pesticides are targeted.

In each MS, there are two monitoring / control programmes: The MACCP, which sets out clear guidelines on the specific control activities that have to be performed by each MS, and a national monitoring programme designed by the competent authority in each MS. Each MS is obliged to report the residues data for the MACCP and their own national programme to EFSA annually.

The residue data are collated, consumer risk assessments are undertaken, and priorities for further testing identified. EFSA publishes a comprehensive annual report on the findings of the MACCP and the results from national testing. At the time of writing the latest published annual report (2010)⁷ showed that 1.6 per cent of the 12,168 samples from the MACCP and 77,075 samples from the national programmes exceeded the MRL (Figure 1). This percentage showed little variation over the four year period between 2007 and 2010 (range 1.2 to 2.3 per cent). Figure 2 shows the results for the samples of each of the 12 commodities analysed in 2010. The relatively high frequency of MRL exceedance for oats was solely due to residues of the chlormequat following use as an anti-lodging agent. The various uses and misuses of chlormequat are discussed in more detail later in this article.  

The Rapid Alert System for Food and Feed (RASFF)⁸

The RASFF system is an online portal that was created to assist countries to notify the Commission if a pesticide residue is found in a food or feed that could be a risk to consumer health. This exchange of information helps MS’s to act more rapidly to a health threat caused by food or feed. As well as risks posed by pesticide residues many other types of chemical, physical and microbiological contamination are reported through this system. Non-compliance with a statutory level or limit does not lead to an automatic notification. MRLs are not safety levels / limits, and an additional assessment of risk is undertaken to determine if the non-compliant residue could pose a risk to consumers.

There are three types of notifications for pesticide residues:

• An ‘alert notification’ or ‘alert’ is sent when a food or feed presenting a serious risk is on the market and when rapid action is or might be required in another country other than the notifying country
• An ‘information notification’ concerns a food or feed for which a risk has been identified that does not require rapid action either because the risk is not considered serious or because the product is not on the market at the time of notification
• A ‘border rejection notification’ concerns a consignment of food or feed that was refused entry into the EU for reason of a risk to human health and also to animal health or to the environment if it concerns feed.

During 2013, there were 452 notifications relating to pesticide residues in food and feed and 75 per cent of these were border rejection notifications. This high percentage of border rejection notifications was probably due to Commission Regulation (EC) No. 669/2009⁹, and subsequent implementing regulations, that has led to an increased level of analysis high risk imported commodities.

Official controls on certain imports deemed to be of high risk

Whenever there is a known or emerging risk from certain imported commodities entering the EU, Regulation 882/2004 gives member states provision to undertake increased levels of control. Commission Regulation 669/2009 and several subsequent implementing regulations list certain foods from specific countries of origin requiring increased levels of controls at designated points of entry into individual countries. In addition to pesticides, residues other contaminants such as particular mycotoxins, metals and illegal dyes are also targeted. The list of pesticide / commodity / country of origin to be targeted for additional testing was drawn up after taking into consideration:

• Data from notifications received through the RASFF system
• Reports by the FVO
• Reports received from third countries
• Exchanges of information between the Commission, Member States and EFSA.

The level of additional monitoring is specified in terms of the percentages of consignments that must be sampled and analysed.

European Union Reference Laboratories (EURLs) and their main functions¹⁰

In 2006, the European Commission established four EURLs with the overall objective of improving the quality, accuracy and comparability of the analytical results obtained across official control laboratories.

The main EURL responsibilities are to:

• Provide the National Reference Laboratories in each member state with details of analytical methods
• Organise Proficiency Tests on an annual basis
• Develop and validate new analytical methods
• Develop and keep updated, analytical quality control guidelines
• Organise workshops and training for laboratories in the Member States
• Provide scientific and technical assistance to the Commission, e.g. for the establishment of MACCP
• Collaborate with laboratories responsible for analysing food and feed in third countries.

The responsibility of three of the EURLs is split by commodity:

1. in fruits and vegetables (FV)
2. in cereals and animal feed (C)

• in products of animal origin (AP).

The fourth EURL is responsible for pesticides that are not amenable to multi-residue methods (MRMs) of analysis and require the use of specific, or single, residue methods (SRMs).

Methods of analysis used for monitoring pesticide residues in foods

The majority of pesticides can be analysed using multi-residue methods. These methods typically involve solvent extraction followed gas, or liquid chromatographic separation of any pesticides in the solvent extract from co-extractives from the food matrix. Mass spectrometry is the preferred technique to provide unequivocal identification and accurate quantification of the pesticide residues. Official laboratories are free to choose any MRM to undertake the analysis of food or feed samples, providing that they also adopt the appropriate analytical quality control criteria necessary to ensure the quality and comparability of the results that they generate. These criteria are published in Document No. SANCO/12571/2013¹¹.

In the few cases where important pesticides are not amenable MRMs, specific or single residue methods (SRMs) have to be employed. Examples include: chlormequat, dithiocarbamates, ethephon, glyphosate and maleic hydrazide. A full list of specific methods for SRM pesticides and their relevant metabolites is provided on the EURL website.

Examples of specific issues that have emerged in Europe over the last two decades

Even though the MACCP and many of the national monitoring programmes are ‘risk-based’, the MRL exceedance rate over the past decade has remained low at around two to three per cent. Nevertheless, there have been a number of incidences related to specific pesticide / commodity combinations that have been of interest and warranted further action.

Chlormequat

Chlormequat is a plant growth regulator and its main approved use within the EU is as an anti-lodging agent on cereal crops. Chlormequat inhibits cell elongation, which results in sturdier plants by shortening and strengthening the stems. The treated plants are much more resistant to damage from wind and rain.

Official monitoring provided evidence that it had also been used, illegally, on certain fruits and vegetables to increase the flowering and/or fruit setting but also assisted the Commission establishing reasonable trading levels for the pear industry when it’s use was discontinued.

During the 1990s, chlormequat was widely used on pears in to improve the shape of the fruit and texture of the skin. The introduction of LC-MS instruments in the late 1990s enabled laboratories for the first time to be able to detect and measure residues of chlormequat in samples of fruits, vegetables and cereals. Samples of pears, particularly those originating from Belgium and the Netherlands, were found to contain unexpectedly high residue levels.

At this time, growers were applying multiple treatments on an annual basis. This caused a build-up of chlormequat in the sap of the trees and was accompanied by a seasonal release of chlormequat through the fruit and the leaves. At that time, the EU MRL was 3mg/kg, but it was not unusual to find residues at levels between 10 and 20mg/kg. In July 2001, following advice from EFSA, the Commission introduced a temporary MRL of 0.5 mg/kg, which effectively precluded further use of chlormequat on pears. Monitoring of pears by many countries has shown a gradual decline in residue levels over the last decade and accordingly, the temporary MRL has been reduced gradually and is at present 0.1mg/kg.

As a direct result of the pears issues, increased monitoring for chlormequat further demonstrated a number of illicit uses on other food crops:

• Bunched carrots from the Netherlands in 2000: It was thought that it was used to reduce the length of leaf growth and hence improve the both the appearance and shelf-life of carrots with leaves
• Tomatoes originating from Italy and Spain during the period 2002 -2004: It was thought that, as with pears, the application of chlormequat to tomatoes would improve the shape of the fruits
• Table grapes from India in 2010: Chlormequat is approved for use on grape vines in India to protect fruit buds. However, within the EU it is not approved for use on grape vines (default MRL of 0.05 mg/kg). This led to a number of rejections of consignments at Border Inspection Posts in several EU member states, and significant financial losses were incurred by importers, exporters and Indian growers. EFSA are, at present, assessing what is a safe level of chlormequat in grapes and whether, or not, the default MRL could be raised.

Ethephon

Ethephon is a plant growth regulator that has been approved for use in promoting ripening of a number of fruits and vegetables by decompositional release of ethylene. In the last year, MRL exceedances have recently been reported in samples of sweet/bell peppers (MRL = 0.05mg/kg) because of non-approved use.

Ethephon is approved for use on pineapples to enhance flower production (MRL = 2mg/kg) and on red grapes to enhance fruit colouration (0.7 mg/kg). However, over the past 12 months there have been a number of cases of MRL exceedances for both commodities. During the first three months of 2014, there were nine RASFF notifications pertaining to ethephon residues in red grapes.

Isofenphos-methyl

Isofenphos-methyl is an obsolete, superseded organophosphorus insecticide and all approvals for use within the EU were withdrawn many years ago. In 2007 residues were found in a number of samples of sweet / bell peppers originating from Spain. Because of the high acute toxicity of this pesticide, 30 RASFF notifications were reported between the period January 2007 and June 2008. All the peppers came from the same production area in South East Spain and a number of growers were prosecuted.

Quaternary ammonium compounds (QACs)

QACs are biocides that are commonly used in food processing as disinfectants and during washing, packaging and cleaning of surfaces. Residues of two of these compounds, benzalkonium chloride (BAC-C10, BAC-C12, BAC-C14 and BAC-C16) and didecyldimethylammoium chloride (DDAC-C10) were found in a wide variety of pre-packed fruits and vegetables during the first six months of 2012. At this time there was a default MRL of 0.01mg/kg for both actives and most of the residue levels detected grossly exceeded this value.

In July 2012, following a risk assessment EFSA recommended a higher ‘Temporary MRL’ of 0.5mg/kg. MSs were asked to submit the results of their monitoring and this has shown that most findings are compliant with the new temporary level. Monitoring data collected from member states is also currently being reviewed to help in the establishment of a new MRL.

The future

It was important that once European standards were established setting MRLs across Europe for all the countries responsible for complying with these trading standards also to adopt a more co-ordinated response to check compliance. Working to common analytical and reporting standards and having access to expert advice and support from official laboratories within Europe has improved the overall quality of information available throughout Europe within the last 20 years.

Judging from the results from the MACCP, the comprehensive measures that have been implemented by the European Commission, based on advice from EFSA, to monitor and control pesticide residues in food within the EU appear to be working effectively. However, a number of issues do arise at regular intervals, often because of differences in the usage of pesticides in countries outside the European Union, or on occasions where pesticides that have been authorised for use on certain specified crops have been used on others where there is no authorisation. We now have an integrated system that within the EU to collect and report the data, to alert our neighbouring countries to possible risk issues and to target future monitoring against these objectives. This bodes well for the future as our sources of food are being constantly expanded to meet the increased needs of European consumers.

References

1. http://www.efsa.europa.eu/en/topics/topic/pesticides.htm
2. http://ec.europa.eu/food/plant/gmo/legislation/index_en.htm
3. http://ec.europa.eu/food/fvo/index_en.cfm
4. http://www.afbini.gov.uk/nrl-regulation-882-2004.pdf
5. http://ec.europa.eu/sanco_pesticides/public/?event=homepage
6. http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2012:235:0008:0027:EN:PDF
7. http://www.efsa.europa.eu/en/efsajournal/pub/3130.htm
8. https://webgate.ec.europa.eu/rasff-window/portal/?event=SearchForm&cleanSearch=1
9. http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2009:194:0011:0021:EN:PDF
10. http://www.eurl-pesticides.eu/docs/public/home.asp?LabID=100&Lang=EN
11. http://www.eurl-pesticides.eu/library/docs/allcrl/AqcGuidance_Sanco_2013_12571.pdf

About the author

Stewart Reynolds is a Senior Scientist within the Food Quality and Safety Programme at the Food and Environment Research Agency, York, UK. Stewart has worked for four different government laboratories and has more than 35 years’ experience in the analyses of foods for a wide variety of chemical contaminants. He is a member of the Advisory Group for the European Union Reference Laboratories (EURL) for Pesticide Residues in Food, a member of the Scientific Organising Committee for the European Pesticide Residues Workshop (EPRW), and an assessor for the UK Pesticide Residues in Food (PRiF) committee.