Overview
ISO 6000:1981 provides practical guidance for the outdoor storage of round-headed cabbage (Brassica oleracea var. capitata, white and red). The standard covers pre-harvest and harvest measures, drying and handling, construction and operation of clamps (temporary outdoor silos), and monitoring and termination of storage to maintain quality for consumption or industrial use. Annex A lists recommended long-keeping varieties; Annex B discusses the influence of production area and unforeseen storage difficulties.
Key topics and technical requirements
- Harvesting and preparation
- Harvest in dry weather at temperatures below 10 °C; stop irrigation at least 15 days before harvest.
- Cut stems 1–2 cm below outer leaves; remove dead or damaged outer leaves.
- Dry harvested heads in a ventilated frost‑protected area 36–48 hours if needed to reduce brittleness and disease risk.
- Suitability and sizing
- Store whole, sound, clean, undamaged heads; ideal mass ~2–2.5 kg.
- Late cultivars and cabbages from light/semi-compact soils are generally better for storage.
- Clamps and ventilation
- Types: underground clamps, soil-surface clamps, with or without ventilation channels.
- Ventilation options: horizontal channels (20–30 cm internal dimensions) or vertical channels (15–20 cm, 150–180 cm high). Channel spacing guidance provided.
- Clamp dimensions and layout guidance (width, height, length) are given as informational ranges rather than prescriptive values.
- Covering and insulation
- Foundation: 10–15 cm clean straw layer or open‑work crates.
- Straw cover 20–25 cm loose over clamp; increase earth/straw thickness when external temperatures fall below freezing.
- Protect against cracks, gaps, snow and uneven melting-signs of putrefaction.
- Storage environment and monitoring
- Optimum temperature: 0 to +1 °C; avoid prolonged freezing and temperatures >5–6 °C.
- Optimum relative humidity: 85–90% (prefer slightly higher).
- Temperature checks: at least three times weekly in autumn, twice weekly in winter; thermometer introduced to reach the upper surface of heads.
- Sorting and termination
- Remove and grade carefully by hand; discard heavily diseased or frozen heads. Open clamps and dismantle when putrefaction or prolonged warm conditions occur.
Applications and users
ISO 6000 is directly useful for:
- Farmers and growers planning post‑harvest handling
- Post‑harvest managers and cooperatives designing outdoor storage clamps
- Agronomists and extension advisors issuing practical storage recommendations
- Food industry and processors sourcing long‑keeping cabbage
- Quality inspectors and standards implementers assessing storage practices
Related standards
Guidance was produced by ISO/TC 34 (Agricultural food products). For comprehensive post‑harvest systems, consult other ISO guidance on agricultural product handling and cold‑chain management.