Overview
ISO 7700-2:2011 - "Food products - Checking the performance of moisture meters in use - Part 2: Moisture meters for oilseeds" specifies a standardized procedure to verify the in-service performance of moisture meters used to measure moisture content in oilseeds. It is a verification method - not a pattern approval or initial calibration standard - and uses a laboratory reference method (ISO 665) to compare meter readings with true moisture content. The verification results guide decisions to accept, fully check, or repair a moisture meter in operational use.
Key topics and requirements
- Scope: Applies to moisture meters in service for oilseeds; excludes initial calibration and pattern approval.
- Reference method: Uses ISO 665 (determination of moisture and volatile matter) as the laboratory reference to establish true moisture values.
- Sampling and sample prep:
- Use at least two oilseed species; for each species select at least two samples with different moisture levels within the meter’s measurement range.
- Clean and homogenize samples; use specified glass bottles, sieves, sample divider and thermometer.
- Measurement procedure:
- Determine an initial reference moisture (sample B) by ISO 665.
- Stabilize sample and meter temperature (recommended ambient 15–25 °C unless manufacturer specifies otherwise).
- For each test sample (A minus B) take at least three successive meter readings, remixing between readings.
- After meter checks, take a final reference sample (C) and re-determine moisture by ISO 665.
- Reuse limits for test portions:
- A test portion can be used up to 15 times if reference moisture < 12%, 9 times if 12–20%, 6 times if > 20%.
- Performance limits (Maximum Permissible Errors, MPE):
- Oilseeds other than sunflower: ≤10% moisture → ±0.7% (absolute); >10% → ±(0.4% + 3% of true value).
- Sunflower seeds: ≤10% moisture → ±0.8% (absolute); >10% → ±(0.4% + 4% of true value).
- Reporting: Test report must identify the meter, date/place, operator, temperature, full results and measurements, sample identification, method reference, and any test incidents.
Applications and users
ISO 7700-2:2011 is practical for:
- Quality control teams at oilseed processing plants and storage facilities
- Laboratory personnel performing routine verification of moisture meters
- Grain and oilseed traders and inspectors validating on-site meters
- Equipment manufacturers and service technicians performing field checks
- Regulatory bodies and metrology labs that oversee measurement conformity
Using this standard helps ensure reliable moisture readings for drying, storage decisions, trade acceptance, spoilage prevention, and safety compliance.
Related standards
- ISO 665 - Oilseeds: determination of moisture and volatile matter (reference method used in ISO 7700-2)
- OIML R59 - Specifications for moisture meters (pattern approval / built approval guidance)
Keywords: ISO 7700-2:2011, moisture meters for oilseeds, checking performance, moisture content, ISO 665, verification procedure, maximum permissible errors, oilseed quality control.