Limiting chemical residues in food
The role of Maximum Residue Limits
Chemicals in food
To produce high-quality, low-cost food, farmers use chemicals to control crop attack by insects, disease and weeds and to maintain healthy farm animals. Residues from these chemicals can find their way into the food supply. Within Australia, the Australian Pesticide and Veterinary Medicines Authority (APVMA) and Food Standards Australia New Zealand (FSANZ) ensure that the use of chemical products and any subsequent chemical residues in food are safe for human consumption.
New Zealand has its own separate and independent system of regulating the use of chemicals in primary production.
Agricultural and veterinary use of chemicals in Australia
Before an agricultural or veterinary product can be used in Australia, its use and sale must be approved by the APVMA. The APVMA approves the conditions for use of chemicals by primary producers. These conditions are enforced by State and Territory agriculture or environment agencies.
The APVMA also sets levels at which residues of chemicals are allowed to be present in the final food. These levels are expressed as maximum residue limits ( MRLs ) - the highest residue that could possibly result from using the chemical in the manner approved by the Australian Pesticide and Veterinary Medicines Authority. The Australian Pesticide and Veterinary Medicines Authority sets MRLs after a thorough examination of scientific data associated with the chemicals and residue trials, assessment of occupational health and safety aspects of usage, and after considering the results of exposure assessment studies. The concentration is expressed in milligrams per kilogram (mg/kg) of the food.
MRLs are not direct public health limits. This means that MRLs are normally set at levels well below those that would cause an adverse health effect. MRLs act to protect public health and safety by ensuring that residues are no higher than is necessary for effective control of pests and disease. Exceeding the MRL may be an indication that a chemical has been misused. When incorporated into food legislation, the MRL is the highest concentration of a chemical residue that is legally permitted or accepted in a food.
Safety of chemical residues in food
The APVMA notifies FSANZ of new or changed MRLs so that they can be considered for listing in the Food Standards Code. This listing is necessary before the treated produce containing residues can be legally sold in Australia.
An MRL does not indicate the amount of a chemical that is always present in a treated food, but it does indicate the highest residue that is legally allowed.
Before FSANZ recommends an MRL for listing in the Code, it must be satisfied that the residues of the chemicals do not represent an unacceptable risk to public health and safety. FSANZ will not recommend a variation of the Food Standards Code to include an MRL if the estimated dietary intake of chemical residues (dietary exposure) by consumers shows an unacceptable risk to human health.
In its assessment, FSANZ considers the dietary exposure of consumers to chemical residues from all foods in the diet by comparing the dietary exposure with the relevant health standard. FSANZ conducts dietary exposure assessments according to internationally accepted practices and procedures.
Changes to maximum residue limits
Maximum residue limits for chemicals in foods are listed in Standard A14 of Volume 1 and Standard 1.4.2 of Volume 2 of the Food Standards Code. If an MRL for a chemical residue is not listed for a certain food, there must be no detectable presence of that chemical in the food.
MRLs need to be altered from time to time, reflecting the changing patterns of agricultural and veterinary chemicals available to farmers. Such changes arise from the development of new chemical products and crop uses and the withdrawal of older products. FSANZ must be satisfied that any changes to the residues and MRLs do not represent an unacceptable risk to public health and safety before recommending a variation to the Food Standards Code.
All changes to the Food Standards Code require FSANZ' s recommendations to be subjected to scrutiny through a public consultation process. Proposed changes to MRLs are outlined in reports posted on the FSANZ' website and comments invited from interested individuals and organisations. Only after submissions have been considered, and changes made to FSANZ'' s recommendations where appropriate, are the proposed changes referred to the Ministerial Council for decision.
MRLs for New Zealand
Food produced in New Zealand must comply with the New Zealand ( Maximum Residue Limits of Agricultural Compounds ) Mandatory Food Standard 1999. Under the Trans Tasman Mutual Recognition Arrangement (1998), food produced in New Zealand that complies with the New Zealand MRL regulations can be legally sold in Australia. Similarly, food produced in Australia that complies with MRLs in the Food Standards Code can be legally sold in New Zealand.
The NZ MRL standards can be found by following this link:http://www.nzfsa.govt.nz/policy-law/legislation/food-standards
Further information
The Food Standards Code, containing Standard A14 and Standard 1.4.2 Maximum Residue Limits (Australia only), can be accessed at www.foodstandards.gov.au.
( updated September 2003 )