FOOD PACKAGING: SMART PACKAGING
Diagram
Active and intelligent packaging: doing something, or telling something
Active packaging
The pack changes the food environment: it absorbs oxygen, gives off a gas, or controls moisture inside the pack.
↓
Intelligent packaging
The pack monitors and reports the condition of the food or the pack, for example with a colour change or a sensor.
↓
The difference
Active packaging acts on the food. Intelligent packaging tells the user about the food. One pack can do both.
Figure 1: A pack that acts on its contents compared with a pack that reports on its contents. Drawn in our own style from Robertson, Food Packaging: Principles and Practice, 2nd ed., CRC Press, 2005, and Lee, Yam and Piergiovanni, Food Packaging Science and Technology, CRC Press.
Introduction
Active packaging and intelligent packaging are the two kinds of smart packaging, and they are often confused because both go beyond a plain container. Active packaging changes the environment inside the pack: it absorbs oxygen, absorbs moisture, gives off carbon dioxide, or releases a preservative, so the food keeps longer. Intelligent packaging monitors the food or the pack and reports what it finds, for example by changing colour when the temperature has been too high or when gas inside the pack has changed.
The core difference is action against information: active packaging does something to the food, while intelligent packaging tells someone about the food. A single pack can carry both, for example an oxygen absorber plus a colour indicator that shows the absorber is still working.
Quick comparison
Table 1: Active packaging compared with intelligent packaging
| Aspect | Active packaging | Intelligent packaging |
|---|---|---|
| What it does | Changes the food environment inside the pack | Monitors and reports the condition of the food or pack |
| Example | Oxygen absorber sachet inside the pack | Colour indicator that changes when oxygen returns |
| Effect on the food | Direct: it slows spoilage or oxidation | None directly: it only gives information |
| Effect on shelf life | Extends shelf life | Does not extend shelf life by itself |
| Who benefits | The food, by staying fresher longer | The maker, seller and buyer, by knowing the condition |
| Typical parts | Absorbers, emitters, moisture control layers | Indicators, sensors, time temperature labels |
| Needs power | No, it works by chemistry | Usually no, colour indicators work without power |
| Cost | Adds the cost of the active part | Adds the cost of the indicator or sensor |
| Food example | Oxygen absorber in a pack of dried food | Freshness indicator on a pack of chilled meat |
| Can they combine | Yes, one pack can carry both | Yes, one pack can carry both |
Scientific explanation
Definition
Active packaging is packaging that deliberately changes the environment around the food, by absorbing or releasing substances, to extend shelf life or improve quality. Intelligent packaging is packaging that monitors the condition of the food or its environment and gives information about it.
Working principle
An oxygen absorber takes up the oxygen left inside the pack, so oxygen needing microbes and oxidation are slowed. A moisture absorber takes up water vapour, so the food stays crisp or dry. A carbon dioxide emitter gives off gas that slows microbes. An intelligent indicator works the other way: a dye changes colour when oxygen returns, when the temperature rises too high, or when the gas inside the pack changes, so the change can be seen without opening the pack.
Apparatus
The books name no single machine for active or intelligent packaging. The active parts are sachets, labels or layers built into the film, and the intelligent parts are indicator labels, sensor tags and time temperature indicators fixed to the pack.
Measurement procedure
The books name no single standard test that compares the two kinds. In practice an active pack is checked by measuring the oxygen or moisture level inside the pack over time, and an intelligent pack is checked by seeing whether the indicator changes correctly when the condition it monitors changes.
Factors affecting readings
For active packaging, the result depends on how much absorber is present, on the barrier of the film, and on the storage temperature. For intelligent packaging, the result depends on the indicator being matched to the food: an indicator that changes too early or too late gives the wrong message.
Formulas and calculations
The books read give no formula for active against intelligent packaging. The comparison is made from the working principle: active parts change gas or moisture levels inside the pack, and intelligent parts report a change in condition. No number for absorber capacity or indicator timing is given here, because those numbers are set for each product and pack.
Industrial applications
- Active packaging: oxygen absorbers in packs of dried foods, nuts and cured meats, to slow rancidity and mould.
- Active packaging: moisture absorbers in packs of biscuits and snacks, to keep them crisp.
- Active packaging: carbon dioxide emitters in packs of fresh meat and fish, to slow microbes.
- Intelligent packaging: time temperature indicators on chilled foods, to show whether the cold chain was broken.
- Intelligent packaging: freshness and gas indicators on meat and fish packs, to show a leak or spoilage gas.
Advantages and limitations
- Active packaging, advantage: extends shelf life by acting on the cause of spoilage inside the pack.
- Active packaging, limitation: adds cost and a part inside the pack, and the active part can run out before the food is eaten.
- Intelligent packaging, advantage: gives clear information about freshness and handling without opening the pack.
- Intelligent packaging, limitation: it does not make the food keep longer, and a wrong or misread indicator can mislead the buyer.
FAQ
Does intelligent packaging make food last longer?
No. It only reports the condition. It is the active part, if there is one, that extends shelf life.
What is an oxygen absorber?
A small sachet or label inside the pack that takes up oxygen, so microbes that need oxygen and oxidation are slowed.
What is a time temperature indicator?
A label that changes colour or moves if the pack has been too warm for too long, showing that the cold chain may have been broken.
Can one pack be both active and intelligent?
Yes. A pack can carry an oxygen absorber and also carry an indicator that shows whether oxygen has returned.
Is a sachet inside a food pack safe?
The books describe absorbers as parts of the packaging system. They are not food, and the pack must be designed so the active part does not mix with the food.
References and further reading
- Fellows, P., Food Processing Technology: Principles and Practice, Woodhead Publishing (FTN book on disk).
- Robertson, G. L., Food Packaging: Principles and Practice, 2nd ed., CRC Press, 2005 (Google Books page read: Active and Intelligent Packaging, p. 285).
- Lee, D. S., Yam, K. L. and Piergiovanni, L., Food Packaging Science and Technology, CRC Press (Google Books page read: Ch. 15, Active and Intelligent Packaging, p. 445).
