FOOD PACKAGING: LEVELS OF PACKAGING
Diagram
Three layers of packaging around a food
Primary packaging
The pack that touches the food: a bottle, jar, pouch or wrapper that holds one unit of food.
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Secondary packaging
The pack that groups primary packs together: a carton or box holding several bottles or jars.
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Tertiary packaging
The pack for transport and storage: a pallet, a stretch wrapped load, or a large outer case holding many secondary packs.
Figure 1: The three levels of packaging, from the food outward to the pallet. Drawn in our own style from Mallett, Frozen Food Technology, Springer, 1993, Ch. 3, Packaging of Frozen Foods, and Fellows, Food Processing Technology: Principles and Practice, Woodhead Publishing.
Introduction
Primary, secondary and tertiary packaging are the three levels of packaging around a food, counted outward from the food itself. Primary packaging is the pack that touches the food and holds one unit, such as a bottle, jar or pouch. Secondary packaging groups primary packs together, such as a carton holding six bottles. Tertiary packaging holds secondary packs together for transport and storage, such as a pallet of cartons wrapped in stretch film.
The core difference is position and purpose: primary protects the food and sells it, secondary groups and displays it, and tertiary protects the load while it is moved and stored. Each level is removed at a different point: tertiary is removed in the warehouse, secondary is removed in the shop or at home, and primary is removed by the person who eats the food.
Quick comparison
Table 1: Primary, secondary and tertiary packaging compared
| Aspect | Primary | Secondary | Tertiary |
|---|---|---|---|
| Touches the food | Yes, it holds the food directly | No, it holds primary packs | No, it holds secondary packs |
| Example | A bottle, jar, pouch or wrapper | A carton holding several bottles | A pallet of cartons, stretch wrapped |
| Purpose | Protect the food and sell one unit | Group units and help handling | Protect the load in transport and storage |
| Who opens it | The person who eats the food | The shop worker or the buyer | The warehouse worker |
| Printing | Full label, brand, nutrition, date | Brand and handling marks | Handling marks, destination, weight |
| Barrier needed | High, it must protect the food | Lower, it adds some protection | Low, it is mainly for strength |
| Strength needed | Enough to hold one unit | Enough to hold a group of units | High, it must hold a full load |
| Removed where | At home, when the food is used | In the shop or at home | In the warehouse or depot |
| Cost per unit | Highest per unit of food | Lower per unit of food | Lowest per unit of food |
| Food example | A yogurt tub | A carton of 12 yogurt tubs | A pallet of yogurt cartons |
Scientific explanation
Definition
Primary packaging is the packaging that is in direct contact with the food and holds a single unit. Secondary packaging is the packaging that groups primary packages together. Tertiary packaging is the packaging used for bulk handling, transport and storage of secondary packages.
Working principle
Each level has a different job. The primary pack must keep the food safe, keep out air and moisture, and carry the label the buyer reads. The secondary pack must hold the primary packs together so they can be carried and stacked, and it often carries the display for the shop shelf. The tertiary pack must hold a full load together so it can be moved by forklift and stacked in a warehouse without damage. The three levels work together: the tertiary protects the secondary, and the secondary protects the primary.
Apparatus
Mallett describes cartoning machines for primary packaging, corrugated outers for secondary packaging, and machinery for tertiary packaging, such as palletisers and stretch wrap machines. Fellows describes the same three levels in food packaging lines.
Measurement procedure
The books name no single standard test that compares the three levels. In practice each level is checked for its own job: the primary pack is checked for seal and barrier, the secondary pack is checked for strength when stacked, and the tertiary load is checked for stability when moved and stacked.
Factors affecting readings
The result depends on the weight of the food, the strength of the board or film, the number of units in each level, and the conditions of transport. A heavier load needs a stronger tertiary pack, and a long journey needs a more stable pallet.
Formulas and calculations
The books read give no formula for primary against secondary against tertiary packaging. The levels are a way of organising packaging by position and purpose, not a quantity that is worked out by arithmetic. No formula is given here.
Industrial applications
- Primary packaging: a bottle of sauce, a jar of jam, a pouch of soup, holding one unit of food for sale.
- Primary packaging: a yogurt tub or a cheese wrapper, carrying the label the buyer reads.
- Secondary packaging: a carton of 12 yogurt tubs, for carrying and for display on the shop shelf.
- Secondary packaging: a corrugated outer holding bottles, for moving packs from the factory to the shop.
- Tertiary packaging: a pallet of cartons wrapped in stretch film, for transport by truck and storage in a warehouse.
Advantages and limitations
- Primary packaging, advantage: protects the food directly and carries the label and brand.
- Primary packaging, limitation: the most costly level per unit, and it must meet food contact rules.
- Secondary packaging, advantage: makes handling and display easy, and adds protection at low cost.
- Secondary packaging, limitation: it is thrown away before the food is eaten, so it adds material that must be recycled.
- Tertiary packaging, advantage: protects a whole load in transport and makes warehouse handling fast.
- Tertiary packaging, limitation: it never reaches the buyer, so its cost is carried by the whole supply chain.
FAQ
Is a carton of 12 bottles primary or secondary packaging?
Secondary. The bottle is the primary pack, and the carton that groups the bottles is the secondary pack.
What is tertiary packaging?
The packaging used for transport and storage, such as a pallet of cartons wrapped in stretch film.
Does tertiary packaging touch the food?
No. It holds secondary packs, which hold primary packs, which hold the food.
Why have three levels at all?
Because each level has a different job: the primary protects and sells one unit, the secondary groups units, and the tertiary protects the load in transport.
Which level carries the nutrition label?
The primary pack, because it is the pack the buyer takes home and reads.
References and further reading
- Fellows, P., Food Processing Technology: Principles and Practice, Woodhead Publishing (FTN book on disk).
- Mallett, C. P. (ed.), Frozen Food Technology, Springer, 1993 (Google Books page read: Ch. 3, Packaging of Frozen Foods, section 3.4 Primary packaging, p. 62, section 3.6.1 Corrugated outers, p. 68, and section 3.13 Machinery for tertiary packaging, p. 86).
