Feedback
Chemical residues and contaminants in food-producing animals
Queensland has a reputation for high-quality, clean and healthy food production.
To safeguard this reputation, the Queensland Government regulates the use of agricultural chemicals and veterinary chemicals. We also monitor agricultural inputs - such as fertilisers, animal feeds, and plant and animal produce - to ensure that chemical residues and contaminants do not exceed maximum permitted levels.
This guide provides information on common causes of residues and contaminants, and how to manage the signs in food-producing animals.
Aflatoxin poisoning and contaminant issues in production animals
Aflatoxin is produced by moulds growing on grain and nuts, particularly on peanuts and corn (maize). Aflatoxins are a regulated toxin in animal feed worldwide, because these toxins can poison animals if they eat enough. Aflatoxin contamination in food can cause liver cancer in people.
Aflatoxin can be present in:
- peanut by-products
- corn
- sorghum
- bakery waste.
The level of contamination increases rapidly if these items are not kept dry in storage.
If you are dealing with animal commodities that have the potential to cause aflatoxin contamination, you are bound by a general biosecurity obligation under the Biosecurity Act 2014 to minimise the impact of the biosecurity risk posed by aflatoxin to human health or trade in agricultural produce.
Limits of aflatoxin B1 in animal feed
Aflatoxin B1 is the main aflatoxin found in crops. You must control the aflatoxin content of dairy feed, as up to 5% of the aflatoxin eaten by lactating animals is passed into their milk.
In Queensland, levels of aflatoxin B1 in certain feeds are restricted. The Code of practice for feed for food producing animals under the Biosecurity Regulation 2016 sets the maximum levels of aflatoxin B1 to:
- 0.02 mg/kg in peanut shell or screenings and peanut meal in feed for dairy animals
- 0.1 mg/kg in other oilseed meals in feed for dairy animals
- 0.2 mg/kg in other feeds for dairy animals
Commodities that can cause aflatoxin contamination
Although a number of food and animal feed commodities can become contaminated with aflatoxin, peanuts and corn present the most serious risks.
Aflatoxin contamination in peanuts
Aflatoxin contamination is a serious problem in peanuts grown in the Burnett region. If you are in the peanut industry, you can use a variety of measures to minimise the aflatoxin content of nuts destined for human consumption.
Levels of aflatoxin can vary between crops and plants because:
- hay derived from irrigated crops produces less aflatoxin
- seasons with mid-to-late droughts often present a high risk in rain-fed crops - which increases contamination
- drought-stressed crops can contain more than 100mg/kg of aflatoxin
- the leaf and stalk contain little toxin, so levels can vary depending on the number of peanut pods.
You can minimise the risk of aflatoxin contamination in milk by:
- limiting peanut meals and peanut hay to
- 10% of the daily diet for dairy cows
- 25% of the total diet for mature beef cattle
- not feeding cattle peanut meals and peanut hay for 2 weeks before sending them to slaughter.
Aflatoxin poisoning has occurred in pigs, calves and, less often, adult cattle.
Aflatoxin contamination in corn (maize) and sorghum
Corn and sorghum can become contaminated, particularly in drought conditions. The concentrations present at harvest are usually not enough to poison production animals. But if the grain is damp or not aerated properly, aflatoxin can rapidly increase in hot spots in storage.
Aflatoxin contamination in other crops
Other crops, such as wheat, barley and oilseeds, can be contaminated with aflatoxin if they become mouldy in storage. The contamination levels in these crops is much less than the levels in peanuts and corn.
Minimising aflatoxin contamination in meat and milk
The risk to the health of production animals is generally quite low if grain and mixed feeds are stored properly. The risk increases during droughts when the aflatoxin content of some crops increases and more crop by-products are fed to production animals.
Cattle that eat large quantities of grain are at a slightly higher risk of having aflatoxin residues in the offal. The animal remains contaminated for 1-2 weeks.
Grass, silage and pasture hay do not contain aflatoxin. When you purchase grain or mixed feed, ask for a commodity vendor declaration. This is written assurance from the supplier that the grain or feed meets regulated standards for aflatoxin.
Managing aflatoxin levels in dairy cattle
Consumer concern about food safety and contaminants in general is increasing. The dairy industry conducts aflatoxin testing of milk as part of the Australian Milk Residue Analysis (AMRA) survey. The sensitivity of tests that detect contaminants is rapidly increasing. Aflatoxin contamination is not destroyed by milk pasteurisation and will transfer into powdered milk, yoghurt, and other milk-based products.
Milk contamination could have severe economic consequences for you – the farmer – and the industry as a whole. To minimise the risk you should:
- limit the use of peanut meals and their by-products in dairies
- ensure feed grain is stored in conditions that avoid mould growth
- harvest grain at the recommended moisture content, dry if necessary, and maintain good aeration and insect control
- regularly clean feed bins.
Pasture-based beef, sheep and dairy production systems have a low risk because aflatoxins are not produced in pasture, grass hays and silage.
Also consider...
- Read more about aflatoxicosis.
Preventing chemical residues in food-producing animals while drought feeding
Take care when purchasing stockfeed (fodder) during drought or dry conditions. At these times, you may need to source new and alternative feeds for food-producing animals. Feed for animals is often sourced from by-products of agricultural and horticultural crops and may carry an increased risk of chemical residues and contaminants that could affect food-producing animals.
You may not know what chemicals were used on the crop or how the feed was produced, so ask the feed supplier about the risk of residues or contaminants during drought periods.
Written assurance from suppliers of feed
You should ask for a commodity vendor declaration (CVD) from the feed supplier. Although suppliers do not legally have to give you a CVD, you should ask for one so that you have written details of the chemicals used during production. If a supplier refuses to give you a CVD, you can:
- source feed from another producer
- source fodder from an accredited fodder scheme
- have the feed tested for chemical residues and contaminants
- only feed the by-product or fodder to breeders or cattle that are not entering the food chain immediately. Slaughter withholding periods vary depending on the chemical and the level in the feed. In most, but not all, cases, withholding stock from slaughter on known clean feed sources for 60 days will be enough.
Additional testing and documentation for chemical residues and contaminants
During drought, you can introduce additional safeguards to monitor the chemical residue and contaminant status of your cattle. This can involve increased testing and fulfilling obligations when you sell the cattle.
Make sure you accurately complete relevant chemical and contaminant sections on vendor declarations to ensure that buyers can make informed decisions about the risks associated with the commodity or animals.
Restrictions on feeding food-producing animals
Cotton trash
The Australian Pesticides and Veterinary Medicines Authority (APVMA) have issued permit PER87001 that allows the use of cotton trash to be fed to livestock so long as the livestock are put on clean feed for 60 days prior to slaughter.
Animal protein meals for ruminants
It is illegal to feed restricted animal material (RAM) to ruminants. RAM includes meat and bone meal, blood meal, fish meal, poultry meal, feather meal, compounded feeds made from these products and most pet foods.
The ban on feeding RAM to ruminants has been put in place nationally to:
- prevent the potential spread of transmissible spongiform encephalopathies (TSEs), including bovine spongiform encephalopathy (BSE, also known as 'mad cow disease') in Australia
- ensure that our meat and meat products continue to have access to domestic and international markets.
The requirements of the ruminant feed ban for livestock owners include that they:
- must not feed restricted animal material (RAM), including animal meals, to ruminant animals
- must ensure ruminant animals are not fed any animal feed that has the positive RAM statement, which is:
'This product contains restricted animal material - DO NOT FEED TO CATTLE, SHEEP, GOATS, DEER OR OTHER RUMINANTS'.
- when selecting proprietary animal feed, should only choose those products designed and labelled specifically for feeding to ruminant animals
- should not feed ruminants foods formulated for dogs and cats because they are likely to contain RAM, even when there is no positive RAM statement.
Also consider...
- Read more about the ruminant feed ban requirements for livestock owners.
- Find out more about stock feed, fodder crops, grain and pasture treatments.
- Read about chemical residue risk assessment.
- Learn about looking after the welfare of your livestock in dry periods.
Restriction on feeding cannabis to food-producing animals
The rules that regulate the feeding of cannabis to food-producing animals ensure that meat, milk and eggs are free of tetrahydrocannabinol (THC), the active ingredient in cannabis. These rules are defined in the Code of practice for feed for food producing animals made under the Biosecurity Regulation 2016.
Cannabis that can be fed to food-producing animals
You are allowed to feed food-producing animals:
- harvested or treated cannabis plants from which all leaves, flowering heads and seeds have been removed
- denatured industrial cannabis seed
- the oil extracted from denatured industrial cannabis seed
- meal ground from denatured industrial cannabis seed.
Cannabis that cannot be fed to food-producing animals
You must not feed food-producing animals, or allow animals to access:
- any cannabis plant that still has leaves, flowers or seeds attached
- 'failed' industrial cannabis crops left unharvested in a growing paddock
- cannabis seed that can produce cannabis plants - seed that has not been denatured.
Food-producing animals reared near industrial cannabis plants
If you are growing cannabis plants and animals are being reared on your property or your neighbour's property, you must take reasonable steps to keep the animals away from your crop. You may need to build a fence to secure the crop.
© The State of Queensland 1995–2024
- Last reviewed: 08 Sep 2021
- Last updated: 08 Sep 2021