Agricultural compounds & residues
What are agricultural compounds?
Agricultural compounds can be natural or synthetic and can include:
- veterinary medicines
- fertilisers and plant growth regulators
- pesticides (fungicides, herbicides and insecticides).
The use of agricultural compounds
Approved agricultural compounds are used by conventional and organic farmers and growers to:
- improve the quantity and quality of produce
- keep animals and crops healthy
- reduce the spread of diseases, weeds, parasites and other pests.
Agricultural compound use is an integral component of food security, allowing countries to feed people and livestock economically and efficiently. They also help secure the food supply and ensure countries like New Zealand can maintain an economy based on food exports.
Using agricultural compounds helps to:
- maintain yields from season to season by managing pest and disease outbreaks and weather-related effects
- maintain animal welfare by protecting animals from diseases
- minimise the formation of toxins, like mycotoxins, in plants that are defending themselves against pests or disease. These toxins can potentially make people and animals ill.
Agricultural compounds may also be used to prevent and eradicate biosecurity incursions.
Agricultural compounds can leave residues
Because they must be in place long enough to do their job, chemical residues from agricultural compounds can remain in meat, fruit or vegetables at the time of harvest or slaughter. With improving analytical techniques we are now able to see minuscule levels of chemicals if they remain after treatments.
Before any agricultural compound can be used in New Zealand, it has to be approved for use under the Agricultural Compounds and Veterinary Medicines Act 1997. Agricultural compounds are also controlled under other legislation, including the:
- Food Act 2014
- Hazardous Substances and New Organisms Act 1996
- Biosecurity Act 1993
- Animal Products Act 1999
- related regulations and standards — such as the Animal Products Notice: Contaminant Specifications and the Food Notice: Maximum Residue Levels for Agricultural Compounds.
The legislation includes penalties for misuse of agricultural compounds.
Agricultural compounds can be used only if their benefits (for food production and storage) outweigh risks from residues for people and livestock.
Tests required for all new agricultural compounds
Companies applying to register new agricultural compounds or seeking approval for new uses of existing compounds must submit detailed scientific data from studies of the compounds. These studies must meet high regulatory standards. MPI thoroughly assesses the studies and any additional information (such as information on the use of the product overseas or similarities to already registered compounds) before approving the new compound or use.
Data from the studies must demonstrate:
- the lowest amount of compound that can be used to get the maximum benefit for each use
- what residue levels may remain in food at harvest or slaughter so a withholding period (time between the last application and harvest or slaughter) can be set
- the shelf stability of the commercial form of the compound, suitability of its ingredients, and quality control during manufacture.
The residues are compared with health-based guidance values set by the New Zealand Environmental Protection Authority (EPA) to confirm whether they are acceptable in-diet. Acceptable residue limits are then set and recorded in the Maximum Residue Levels Food Notice under New Zealand law.
MPI assesses all the studies in tandem with the EPA which assesses the toxicity of the product and its safety to users and the environment.
MRLs must not exceed health standards
While MRLs are not specifically set as health limits, before any MRL is proposed, MPI will check it against the reference health standard for relevant foods. Reference health standards are the amount of a specific chemical – like a food additive or agricultural compound – experts have decided is safe for a person to eat each day over their lifetime.
MRLs keep residue levels to a minimum
MRLs are one tool used to make sure food producers follow good agricultural practice. Foods that breach the MRL are not necessarily unsafe but could have been better produced.
MPI investigates any MRL breaches and, depending on the amount of residue found, may:
- recall a product
- advise the public of the risk
- seize the products
- suspend production.
We may also take legal action.
Even if you do buy food with residues above the MRL, in most cases the storage time, washing and cooking of the food will significantly reduce residue levels.
Residue levels in New Zealand
MPI monitors and tests residue levels in a random selection of food sold in New Zealand — as well as New Zealanders' overall exposure to chemicals — through surveys and programmes, including the:
- National Chemical Residues Programme
- Food Residues Surveillance Programme
- National Chemical Contaminants Programme
- New Zealand Total Diet Survey.
Residues in New Zealand are similar to levels overseas
Foods sold in New Zealand have similar or lower residue levels than are found in other countries. However, it can be difficult to compare results between countries because of varying climate conditions, pest types and agricultural production methods.
New Zealand's use of some 'banned' chemicals
Some agricultural compounds used in New Zealand aren't used in other countries. This doesn't mean they're 'banned' for food safety reasons.
An agricultural compound may not be registered in another country because:
- the country doesn't grow the crops it's used on
- the country doesn't have the pest it protects against
- the country has other products that are used for the same purpose
- it poses a specific threat to the country's wildlife or environment. For example, 1080 is very toxic to dogs so is banned in the US to protect native coyotes.
Reducing your residue intake
Studies of the New Zealand diet show New Zealanders' intakes of residues and other chemicals in food are well below safety levels. If you're still concerned, you can reduce your exposure by:
- thoroughly washing all produce, especially if eating raw
- following manufacturers' instructions for mixing chemicals and waiting for the entire withholding period
- using compost from reputable firms – make sure it is well composted and mixed into the soil
- eating undamaged produce that looks fresh – healthy plants and animals are likely to produce fewer or lower levels of natural toxins
- making sure foods are properly cooked.
Find out more
Who to contact
If you have questions about agricultural compounds and residues, email firstname.lastname@example.org.