Temperature

Preserved foods require particular temperature, humidity/moisture and possibly ventilation conditions

• At temperatures < -2°C there is a risk that cans may blow due to freezing of their contents (ice expansion).
• At temperatures > 20°C, cans may blow due to heating which results in thermal expansion.

Long-term exposure to high temperatures may lead to:

• separation, settling
• marbled effect in preserved foods which have a high protein content (meat, fish, peas, beans) due to sulfidic corrosion. This occurs if the sulfur components of the proteins act on tin or sheet iron
• Where container transport is used, the risk of blowing due to the action of heat and frost is greatest in the vicinity of the container roof. The additional moisture released as a result of leakage due to blowing aggravates wettening of cartons and corrosion of cans.

• Canned foods require particular temperature, humidity/moisture and possibly ventilation conditions
• The cartons must be protected from all forms of moisture (seawater, rain and condensation water) and from excessive humidity levels. Typical patterns of moisture damage to a cargo of preserved foods are as follows:
• loose, mildewed, unattractive labels
• mold on and in cartons
• crushed cartons, due to moisture penetration, leakage, total loss
• corroded, discolored cans; corroded cans are unsalable
• If the glue used to stick on the labels is not acid-resistant, corrosion is encouraged even at normal humidity levels. High-grade, water-resistant adhesives must be used for labels.
• Corrosion damage arising during overseas shipment of cans in containers

Where preserved foods are transported in containers, the causes of condensation are as follows:

• Excessive water content in cartons, pallets and wooden dunnage 
• Temperature gradients within the cargo stack, leading to cargo condensation
• Drop in temperature in the peripheral zones of the container, in particular at the container roof, leading to container condensation
• Part-loads with different temperatures, e.g. simultaneous stowing of relatively cold food cans and relatively warm hygroscopic goods.
• Containers should not be packed during precipitation. It is essential not to stow any wet or snow-covered cargo units in the containers.
• The wooden flooring of the containers must be absolutely dry. The water content of the flooring should be 12%.
• To protect the cargo from condensation water dripping down from the container roof, it may be helpful to use anti-condensation films or a packing paper lining, or silica gel bags (as recommended by WFP).

• Preserved foods require particular temperature, humidity/moisture and possibly ventilation conditions
• If the product is at "shipping dryness", i.e. the water content of the paperboard cartons is 5 - 8%, ventilation is not normally required.

• Canned foods are products in which biochemical and microbial processes have stopped and which are isolated from the external environment, as they are in hermetically sealed packaging (cans).

No risk.

No risk.

• Active behavior: Canned foods do not cause odor-tainting, as they are enclosed in hermetically sealed packaging.
• Passive behavior: Canned foods should not be stowed in a hold/container/Wh together with odor-tainting goods.