Frozen Cargo

Effects of temperature on frozen food quality

As a general rule, frozen commodities should be transported and stored at 0°F (-17.8°C). For most products, this temperature provides protection against spoilage and the growth of disease-forming organisms.

Some frozen cargoes need to be carried at temperatures lower than 0°F (-17.8°C) to maintain quality, texture and flavor. Commodities with a high fat content, such as ice cream and surimi, should be carried at -15°F (-26.1°C) or lower.

Low temperature preserves the quality of frozen food (aroma, flavor, texture and appearance) and protects it from spoilage. However, proper temperature management of frozen commodities can only be achieved if the products are properly frozen, packaged and correctly stowed for transit.

Freezing food

Food should be solidly or almost solidly frozen to maintain quality in frozen storage. An unfrozen core, or a partially frozen zone, will lead to deterioration in texture, color, flavor and other properties. Fast freezing leads to superior product quality. Slow freezing results in the formation of large ice crystals that rupture cell walls and result in soft, mushy products.

Damage from thawing

Nothing is more detrimental to frozen foods than repeated freezing and thawing. Proper temperature management is crucial because temperature fluctuations in storage or transit that cause thawing can be damaging to some foods.

Packaging

Appropriate packaging and glazing can protect most foods from freezer burn (surface drying that produces unsightly appearance and nutrient loss), bacterial contamination and the effect of oxygen. Packaging material should not only be impermeable to water vapor and oxygen, but also to volatile flavor substances.

Pre-cooling

The container should be pre-cooled to the appropriate temperature before loading when necessary. Transferring a cold product to a warm container can result in surface thawing and freezer burn. Frozen products should be loaded rapidly, especially in warm weather when ambient temperature may be high. As part of its quality-control procedures, APL requires that the temperature of frozen commodities be 15‰F (-9.4‰C) or less at the time of loading.

Stowing

Frozen cargo should always be stacked as a solid block, leaving no space between packages and sidewalls of the containers.

Ventilation

Fresh air vent must always be CLOSED tight for all frozen cargo shipment.