There is no universal limit for moisture or sand and silica in feed ingredients. Most are set by contract. Indian oilmeal contracts commonly set moisture at around 10 to 12 percent maximum and sand and silica at a few percent maximum, but these are illustrations, not standards.
The right figures depend on the meal, how it will be stored and shipped, and what your feed mill or customer accepts. Some importing countries also set rules on ash or contaminants, so check with your feed authority.
Why moisture matters
- Mould: damp meal supports mould growth, which can produce aflatoxin and other mycotoxins.
- Caking and heating: wet meal can clump and warm up in storage.
- Condensation: moisture leaves the meal during a sea voyage and condenses inside the container.
- Value: you pay for water by weight, and protein per kilogram falls as moisture rises.
- Shelf life: drier meal keeps longer, as covered in what the shelf life of oilmeals is.
What sand and silica means
In the Indian trade, sand and silica is usually measured as acid insoluble ash. It is the mineral residue that does not dissolve in acid after burning the sample, and it is mostly soil and sand.
A high result usually means poor seed cleaning, field soil on the seed, or sweepings added to the meal. In rice bran meal some silica also comes from husk. Sand adds weight without feed value and can wear feed mill equipment.
Do not confuse it with total ash. Total ash includes natural minerals in the meal. Acid insoluble ash isolates the part that is mostly sand.
Setting the figures
Start from your formulation and storage needs, then compare with the supplier's recent test results. A limit far tighter than the plant usually achieves will cause disputes. A limit far looser invites sand and water.
- Moisture: state a maximum and the method, such as oven drying at a stated temperature.
- Acid insoluble ash: state a maximum and call it by name, not just sand.
- Total ash: add a maximum if your customers ask for it.
- Basis: say whether other parameters, such as protein, are as-is or dry matter.
- Remedy: agree a price allowance or rejection if a lot goes over.
Checking at source
Ask the plant how it cleans seed before crushing and whether it adds anything to the meal. Draw samples from several bags across the lot and test at an NABL-accredited lab before loading. The general approach to tolerances is in what tolerances to include for moisture, purity and foreign matter.
Where we come in
We review a plant's past test results, help you set realistic moisture and acid insoluble ash limits, and test sealed lot samples at an NABL-accredited lab before the container is loaded. Ask for a free sourcing review.