Overview
ISO 6664:1983 - "Bilberries and blueberries - Guide to cold storage" provides practical guidance for obtaining optimum cold‑storage conditions for wild bilberries (Vaccinium myrtillus), lowbush blueberries (Vaccinium angustifolium) and cultivated highbush varieties (Vaccinium corymbosum). The standard covers harvesting and handling practices, precooling and storage parameters, preservation options (additives and modified atmospheres), and common storage disorders (annexes describe limits of application and cryptogamic diseases).
Key topics and technical requirements
- Harvesting and handling
- Pick fruits near full maturity: fully coloured, firm, with natural waxy bloom; avoid picking when wet (rain/dew).
- Handle gently and place directly into shallow baskets or solid light packages to avoid bruising and crushing.
- Stack packages to allow uniform air circulation (use duckboards and pallet limits recommended by the store).
- Precooling and putting into store
- Precool as soon as possible after harvest (preferably within 12 hours); forced cold air precooling is preferred to remove field heat.
- Store packages in shade immediately after picking and move to refrigeration quickly.
- Optimum storage environment
- Temperature: recommended optimum between −0.5 °C and +0.5 °C; depending on equipment, storage up to about 4 °C may be used.
- Relative humidity: about 85–90% to limit dehydration while preventing condensation.
- Air circulation: intense circulation during cooling to homogenize temperature; air circulation ratio (per ISO 2169) suggested 30–50 until target temperature reached.
- Storage life and end‑of‑storage care
- Fresh‑market fruits: up to about 2 weeks under optimum conditions; fruits for processing: up to 3 weeks, dependent on cooling speed and storage conditions.
- Gradual warming and light ventilation on removal to avoid surface condensation.
- Additives and preservation
- Modified atmospheres (higher CO2/N2 and lower O2) may be used to slow ripening and control rots.
- The document references use of carbon dioxide (e.g., dry ice) and nitrogen sources (e.g., liquid nitrogen) as preservation means in some cases.
- Disinfect cold‑store and packaging to reduce cryptogamic disorders.
- Diseases
- Annex B highlights storage pathogens: Botrytis cinerea (grey rot) and Penicillium spp.; bruised or overripe fruit are most susceptible.
Applications and users
- Growers and harvest crews (best‑practice picking and handling)
- Packinghouse and cold‑storage operators (facility hygiene, precooling, refrigeration control)
- Food processors and exporters (shelf‑life management, modified‑atmosphere options)
- Quality assurance and postharvest specialists seeking to reduce losses and maintain fruit quality
Related standards
- ISO 2169 - referenced for physical conditions and air circulation definitions in cold stores.
Keywords: ISO 6664:1983, bilberries, blueberries, cold storage, postharvest, Vaccinium myrtillus, Vaccinium angustifolium, Vaccinium corymbosum, storage temperature, relative humidity, precooling, modified atmosphere, Botrytis cinerea.