Agrochemicals

Maximum Residue Limits (MRLs)

The MRL is the maximum concentration of an agrochemical permitted legally in a foodstuff.

Setting an MRL

Governments regulate the use of agrochemicals by setting MRLs for active constituents or by product registration.  Factors, such as good agricultural practice, ADI (Acceptable Daily Intake) and recommendations by the Codex Alimentarius Commission may be taken into account in setting MRLs.

In Australia, the MRL for an agrochemical residue in a particular foodstuff is set to reflect 'good agricultural practice'.  If  producers follow the agrochemical label directions, the resulting food crops should have residues below the permitted Australian MRL.  The MRL is established by applications of a particular agrochemical in field trials and the subsequent measurement of the relevant residues in the harvested crop.  Taking into account these data, other dietary sources of the residue and a safety margin, an MRL is proposed if the ADI will not be exceeded.

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Why do MRLs differ between countries?

Some of the agrochemicals used in the production of grapes in Australia do not have an MRL in overseas markets.  This is often because grapes are not grown commercially in these countries, therefore these agrochemicals are not registered for use on grapes.  As a result, there is no requirement for an MRL for grapes.  Furthermore, when an MRL does exist, it often differs in value between countries.  Therefore, the production of grapes for wine destined for export requires a carefully planned spray program.  When selecting an agrochemical, ensure that its application will not result in a residue that is unacceptable to Australia's major wine markets.  To achieve this, it may be necessary to avoid the use of certain agrochemicals altogether, or to restrict their use.  Some wineries publish a list of preferred agrochemicals and withholding periods for the export wine market.

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Are MRLs for grapes or wine?

MRLs, as yet, rarely have been set for wine and are normally adopted from those set for the raw agricultural commodity.  For wine, this is usually described as 'grapes', 'berries and other small fruits' or 'fruit' in the food standards information that has been obtained from various regulatory authorities in this survey.  The exception is Switzerland, where the MRLs are set for wine.

Unless stated, the MRLs listed in this database are for grapes in general.  In some instances, specific MRLs exist solely for table grapes or wine grapes, and these are noted.

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Glossary

Agrochemical-any chemical, excluding fertilizers, used in agriculture.  For the purpose of this publication, an 'agrochemical' can be a fungicide, insecticide, herbicide, molluscicide (snail/slug killer), plant growth substance or fruit drying agent.

Registered Product-an agrochemical formulation that is commercially available.  The registered product may be made up of one or more 'active constituents' plus other materials, including wetting agents, emulsifiers and inert diluents.  A registration is the legal permission for a particular agrochemical to be used according to the directions on the label.

Residue-the residue is defined by each country and may include traces of the agrochemical applied to the grapevine, as well as any metabolites or break-down products, of that agrochemical.

Some analytical methods convert chemically similar residues to the same end-product.  For example, analysis to determine residues of the dithiocarbamate fungicides (mancozeb, metiram, propineb, thiram, zineb and ziram) produces carbon disulfide, which is then measured.  The residue of dithiocarbamate fungicides is, therefore, defined as carbon disulfide.

Acceptable Daily Intake (ADI)-the daily dosage of a chemical, which, during an entire lifetime, appears to be without appreciable risk on the basis of all the facts known at the time.  These are agreed upon for each agrochemical by the Food and Agriculture Organization of the United Nations and the World Health Organization at their regular Joint Meeting on Pesticide Residues. 

Codex Alimentarius Commission-an international body established by the Food and Agriculture Organization of the United Nations and the World Health Organization, with the objective of upgrading and simplifying international food regulations (Codex Alimentarius means 'food code' in Latin).  Codex MRLs have been set for some agrochemicals in a range of crops, and several countries accept Codex MRLs in the absence of their own.
Visit the Codex Alimentarius Commission homepage. 

European Union-Austria, Belgium, Denmark, Finland, France, Germany, Greece, Ireland, Italy, Luxembourg, the Netherlands, Portugal, Spain, Sweden and the United Kingdom are all members of the European Union (EU). Member nations are obliged to abide by Directives on MRLs issued by the Council of the European Communities. If no EU MRL exists, the food standard of each country should be consulted to determine the residue tolerance.