How to: Safely Package Foods
Packaging for fresh and frozen foods is a vital factor in the cold chain: a low temperature maintained supply chain. The aim is to preserve the food by slowing down any reactions that might cause it to spoil, such as microbial growth.
Chilled food must be kept above freezing but below room temperature, with different limits for different foods. For instance, fish must be kept at no more than 2C, milk at no more than 4C, and meat at no more than 7C. Frozen food must be kept at -18C or colder in order to preserve its storage life.
These temperatures must be kept throughout the cold chain, so transfer from warehouse to lorry, and from lorry to retailer, must be delay-free. Appropriate packaging is essential to keep the chain running smoothly, so here is our breakdown of what you need to consider when packaging up foods.
Packaging in the warehouse
Soon after foods are sourced, they are encased in primary packaging. The exact type of packaging used, however, depends on the nature of the food. Smoked mackerel (chilled), for example, may be vacuum-wrapped in plastic, whereas haddock fillets in breadcrumbs (frozen) may be packed in thin cardboard boxes.
The packaging must withstand the temperature at which the food within needs to be kept. By law, it must protect the food from external hazards, and not affect the food itself. Equally, only the minimum amount of protective, secondary packaging should be used — having as little impact on the environment as possible. Because of food packaging legislation, and the potentially devastating effects of contamination, the packaging used in the cold chain is usually well designed for its purpose.
Some foods may not require primary packaging. For example, freshly picked apples or oranges may be loaded straight into wooden or corrugated cardboard crates, which, under other circumstances, might be used as secondary packaging.
The foods are then transferred to warehouses, where they are put into a cold store: a unit in which a suitable temperature is maintained.
For the transportation and storage of chilled and frozen foods, secondary and tertiary packaging is essential. Examples include cardboard boxes and retail ready packaging, which may be used for foods such as cheese (primary packaging: plastic) or frozen pies (primary packaging: foil trays and thin cardboard boxes). Because secondary packaging will contain several items, it must be strong, with single or double wall corrugated cardboard boxes being popular choices.
Loading and transport
When chilled or frozen foods are ready to be transported in their secondary packaging, they are loaded onto pallets (tertiary packaging). The pallet enables very heavy loads to be lifted, using a forklift truck, into the refrigerated container on the back of a lorry. Temperature monitors may be used on the secondary packaging, and in the container, to ensure that the cold chain is being properly maintained.
When storing the largest packaging at the bottom isn’t an option, place palletised loads of equal height, to minimise gaps, and toppling can be prevented. Wrapping palletised loads with plastic also aids stability. However, with chilled and frozen foods, it is not always possible to achieve this: air needs to circulate within a refrigerated container to keep the cargo fresh. In the case of respiring fresh produce (e.g. fruits and vegetables), the cartons within which it is contained may be designed to allow air movement. Measures such as lashing loads down with straps, and ensuring the container floor has a non-slip surface, may prevent movement.
During transportation, the weight of the whole load is important. The lower the weight, the less fuel will be used, so both emissions and costs will be cut. Using single wall boxes, for example, instead of double wall boxes, will enable a weight saving to be made.
It’s not sufficient for packaging merely to be able to withstand the stresses of the warehouse, loading, and transportation stages: it must be sturdy enough to cope with being unloaded, as well.
Again, the physical properties of the cardboard boxes and pallets enable unloading to be done with ease, thus keeping knocking and tearing to a minimum. A further consideration is the potential for the cold chain to be broken again. Here, the insulating properties of the cardboard enable heat gain to be kept to a minimum while unloading is carried out.
Tertiary and secondary packaging should be easy to remove, so that the primary-packaged chilled or frozen foods can either be taken quickly to the cold store at the retail premises, or straight to the shop floor. Such packaging should also be easy to dispose of, so if it is made of recyclable material, and as little packaging as possible is used, less space will be taken up in bins, keeping the retailer’s waste management costs down.
For any more information about getting the right packaging for your business, check out our Packaging Clinic