Silos, augers and trucks that have held treated fertiliser or products such as pickled (treated) grain can contaminate otherwise clean grain subsequently loaded or moved through that equipment.
PHOTO: Paul Jones
While most growers understand the importance of grain storage hygiene, trucks and augers used to transport and move fungicide-treated seed or fertiliser are sometimes overlooked as a source of potential contamination.
This is resulting in detection of residues of chemicals such as flutriafol and fluquinconazole in grain.
Flutriafol is a fungicide widely used in seed treatments, and as an in-furrow fertiliser and foliar application to control a variety of fungal diseases. Fluquinconazole is a systemic seed dressing for cereals and canola.
Contamination can occur for several reasons, including:
- failure to clean and decontaminate the equipment used to transport grain, such as trucks and augers; and
- inappropriate or off-label use of the chemical, or a use of the chemical that is not covered by the Australian Pesticides and Veterinary Medicines Authority permit. This includes a failure to comply with the withholding period or use at a higher-than-recommended rate.
To manage cross-contamination risks and ensure grain complies with maximum residue limits (MRLs) growers must adhere to the following steps.
- Use only chemical products registered for the crop or for grain storage. Ensure the commodities and infrastructure being treated are specifically approved in the label directions for use. Observe label rates, withholding periods and any other permit conditions.
- Maintain and clean storage sites, in particular silos, augers and trucks that have held treated fertiliser or alternate products such as pickled (treated) grain. Where possible, use different storages and augers to handle and store these products.
- Ensure any contractors involved in the transportation of grain comply with the respective Grain Carriers’ Code of Practice.
- Keep accurate records of all chemical applications (including treatment of fertilisers), chemical storage and cleaning activities on storages, trucks and handling equipment. Complete a Commodity Vendor Declaration form based only on those records.
- Growers should know which market their grain is going into. Importing countries may have lower MRLs than Australia. This is extremely important where growers are signing contracts (including forward contracts). The contract may state that the grower is not to exceed MRLs of the importing country. In some cases, this means growers will be unable to use particular pesticides on that crop or chemicals on storage and handling equipment.
- Clean grain storage and transport equipment.
Always wear appropriate personal protective equipment. The goal of cleaning is to remove any residual dust or chemicals, and there are two methods of doing so.
- Sweeping or using compressed air followed by washing is the best option to safeguard grain transport and storage equipment.
- Compressed air by itself is also effective.
If using contractors for grain transport, ensure they provide a declaration of cleanliness. The Grain Carriers’ Code of Practice requires the carrier to retain records of cleaning and prior loads to determine the risk of chemicals contaminating the truck.
Andrew Weidemann, GPA
03 5385 5089
Steven Field, Victorian Department of Environment and Primary Industries
03 5824 5532
Gerard McMullen, Grain Trade Australia
03 8300 0108
Bill Murray, National Working Party on Grain Protection
0417 540 846
Ian Reichstein, National Residue Survey, Department of Agriculture
02 6272 5668
Australian Grain Industry Code of Practice:
Harvesting equipment clean down guidelines – canola:
Grain Carriers’ Code of Practice:
Managing chemical cross contamination risks:
Test soil and plant tissue before adding zinc
Japan warns barley exporters about residues