Key points
- Every parameter needs limit, method, tolerance and moisture basis.
- Specify only what you can and will verify.
- Version the specification and reference the version in the contract.
The four elements of a usable parameter
Limit (minimum, maximum or range), analytical method reference, tolerance or repeatability allowance, and basis (as-fed or dry matter). Omitting any one of these creates a clause that cannot be applied objectively at discharge.
Specify what you will actually verify
A specification listing thirty parameters when the receiving programme tests five creates a false sense of protection and an unenforceable contract. Align the specification with the verification programme and the laboratory scope.
Physical and packaging requirements
Particle size, flowability, colour, odour, foreign matter, packaging type, marking and pallet configuration affect handling and are legitimate specification items. They are also the ones most often left out and disputed later.
How to do it
- List the nutrient parameters the formulation requires, with limits.
- Assign an analytical method reference to each parameter.
- Define tolerance and the moisture basis for each value.
- Add contaminant, microbiological and physical requirements.
- Define packaging, marking, sampling and acceptance procedure.
- Version, date and approve the document, then reference it contractually.
What to verify
- Each parameter has limit, method, tolerance and basis
- Specification version referenced on the purchase order
- Receiving test panel matches the specified parameters
Risks to manage
- Unenforceable clauses discovered only during a dispute
- Different methods giving different results for the same parameter
- Physical and packaging requirements omitted entirely
Common mistakes
- Copying a supplier datasheet into the contract as the specification
- Specifying parameters no one intends to test
- Leaving the moisture basis unstated
Terms used on this page
- Tolerance
- The permitted deviation from a specified value before a lot is considered non-conforming.
Frequently asked questions
How many parameters should a specification contain?
Those that affect safety, formulation value, processing behaviour or storage stability — and that you will verify. Additional parameters add administrative load without adding protection.
Should tolerances match laboratory repeatability?
Tolerances should account for method reproducibility between laboratories, otherwise routine analytical variation will generate non-conformances that are not real quality failures.
Related reading
Technical references
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