IQF (individually quick frozen)
Also known as: individually quick frozen, fluidised bed freezing
Short definitionFreezing each piece of a small product separately, within minutes. The pieces do not stick together, so any amount can be taken from the pack.
Peas or prawns frozen as a block cannot be separated without thawing. In an IQF tunnel the product is kept airborne on a perforated belt by −35/−40 °C air blown from below, or it travels through fast cold air on a spiral belt. The pieces freeze without touching each other. Frozen fruit and vegetables, prawns, squid, meatballs, meat cuts and chips are made this way.
Tunnel capacity is quoted in tonnes of product per hour, and the tunnel is fed by low-temperature units or a central ammonia or CO₂ system. The project does not end with the tunnel; the product coming out needs a frozen storage room at −18/−25 °C. If the temperature swings in that room, the pieces stick together again and their surfaces dry out. Door traffic and the defrost schedule are planned with this in mind.