Overview
ISO 7562:1990 - "Potatoes - Guidelines for storage in artificially ventilated stores" provides practical, internationally harmonized guidance for storing potatoes in mechanically ventilated warehouses. The standard covers pre-storage preparation, building and equipment requirements, staged storage procedures, ventilation and environmental control, inspection routines, and record-keeping for lots. It is intended for temperate climates and addresses seed, table (consumption) and processing potatoes.
Key topics and technical requirements
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Storage environment and building
- External walls and roofs must be thermally insulated and airtight; a moisture barrier should be placed on the warm side of walls to reduce vapor penetration.
- Minimum clearance of 1 m between the roof and the top of potato heaps or containers.
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Equipment and preparation
- Stores should have loading/unloading/transport systems, ventilation and temperature/humidity control, electrical supply (lighting and power) and graders (calibreuses).
- Premises must be cleaned and disinfected with officially approved chemicals before storage.
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Storage phases and conditions
- Five storage phases are identified including drying, tuber maturation and wound healing, and cooling.
- Maturation/wound healing: about 2 weeks after entry; recommended air temp 12–18 °C with relative humidity 90–95 %.
- General relative humidity: 85–95 %.
- Temperature targets vary by use:
- Seed potatoes: preparation stage to stimulate germination - raise to 10–15 °C over 3–5 weeks with RH 75–80 % and minimum lighting ≈ 75 lx; long-term storage temperature later maintained 2–4 °C.
- Table potatoes (consumption): long-term storage target 4–6 °C (elsewhere noted raising to 12 °C for conditioning), depending on stage.
- Processing potatoes: storage typically 6–10 °C, with conditioning at 15–18 °C if high sugars/dark colour need correction.
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Ventilation rules
- Use interior air, exterior air or a mix. Exterior air may be used only if outside temperature is at least 2 °C lower than inside.
- Ventilation must limit top-to-bottom temperature differences to ≤ 1 °C.
- Before ventilation measure temperature at minimum two points (top and bottom) and outside temperature; stop introducing external air if required; introduced air temperature should not be below 0 °C.
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Inspection and documentation
- Regular visual and equipment checks; remove locally rotting tubers immediately.
- Lot documentation should record: lot number, quality, variety and destination, producer name, storage date, inspection dates and temperature/humidity readings, remarks and sampling data.
Applications and users
Who benefits:
- Potato growers and seed producers
- Bulk storage warehouse operators and designers
- Processors and packers managing raw-material quality
- Agricultural extension services and post‑harvest engineers
Practical uses:
- Designing or retrofitting ventilated potato stores
- Establishing operational SOPs for temperature/humidity control and ventilation
- Training staff on inspection, lot traceability and quality maintenance
Related standards
ISO 7562 was developed by ISO/TC 34 (Agricultural food products). For complete post-harvest management, users typically consult other ISO and national standards on agricultural storage, hygiene and commodity-specific handling published by the same technical committee.
