Is a leak of 50 μm in your packaging acceptable?
When a leak is detected on food packaging, a question often comes up:
Is a leak of 50 μm acceptable?
At first glance, 50 micrometres (μm) appears extremely small. However, this information alone does not make it possible to determine whether a packaging is compliant or not.
In reality, a leak of 50 μm can be tolerable in some applications and problematic in others. It all depends on the packaged product, its shelf life and the expected level of protection.
What does a leak of 50 μm represent?
A micrometer corresponds to one thousandth of a millimeter.
To better visualize:
- A human hair generally measures between 50 and 100 μm in diameter
- A grain of fine flour can measure a few tens of micrometers.
- Many micro-leaks are invisible to the naked eye
A leak of 50 μm is therefore very small. However, its size is not sufficient to assess its actual impact on product preservation.
A small leak can have big consequences
When a packaging is no longer perfectly sealed, exchanges can gradually occur with the external environment.
Depending on the type of packaging, this can cause:
- The oxygen inlet
- The loss of carbon dioxide
- The loss of emptiness
- A change in the internal humidity
- A reduction in the shelf life
However, the speed at which these phenomena occur depends strongly on the product concerned.
Not all products react in the same way
That’s the key point.
The same leak of 50 μm will not necessarily have the same consequences on all foods.
- Snacks and dry products
Let’s take the example of a bag of chips packaged under nitrogen.
A leak can gradually allow oxygen to enter the packaging. The product may then lose some of its crispiness or see the fat oxidise more quickly.
The impact will generally be gradual and mainly affect the sensory quality of the product.
- Dried fruits and dehydrated products
For some products not very sensitive to microbiological development, the consequences of a small leak can remain limited for several weeks.
The main issue often concerns humidity or the preservation of organoleptic qualities.
- Fresh meat under modified atmosphere
The situation is very different for fresh products.
A gradual entry of oxygen or a loss of CO2 can:
- Change product color
- Reduce the effectiveness of protective atmosphere
- Decrease the shelf life
In this case, a small-size leak can have a much greater impact.
- Fish and seafood
These products are among the most susceptible to packaging defects.
Preservation is often based on a precise balance between packaging, protective atmosphere and cold chain.
A micro-leak can degrade this balance much more quickly than on dry products.
Why is there no universal threshold?
It would be practical to state: “A leak of less than 50 μm is acceptable” or “A leak greater than 50 μm must be refused.”
Unfortunately, the reality is more complex.
The acceptability of a leak depends in particular on:
- From the type of product
- Of the targeted shelf life
- Of the type of packaging
- Of the gas mixture used
- Storage conditions
- The company’s quality requirements
Two products with exactly the same leak can therefore have completely different behaviors.
What really matters: the impact on the product
In practice, manufacturers are less interested in knowing the size of a leak than in understanding its consequences.
So the real question is not: “Does the leak measure 50 μm?”
But rather: “Does this leak compromise the quality or shelf life of the product?”
It is to answer this question that companies realize, in particular:
- Aging studies
- Shelf life validations
- Leak tests
- Regular quality checks
Can we detect a leak of 50 μm?
The detection of a micro-leak depends on the method used.
Visual methods, such as the water basin test, make it possible to identify certain leaks but can show their limits for the weakest defects.
Instrumented methods generally offer better repeatability and greater sensitivity, while providing usable results for quality monitoring.
The choice of method will depend on the level of requirement sought and the sensitivity of the packaged product.
The importance of defining your own acceptance criteria
Each company must determine which leakage levels are compatible with its products and conservation objectives.
This approach is generally based on:
- The DLC studies
- The validation tests
- The regulatory requirements
- Feedback from the field
A relevant threshold for chips will not necessarily be suitable for fresh meat or seafood.
Conclusion
A leak of 50 μm is neither acceptable nor unacceptable in nature.
Its impact depends primarily on the packaged product, its packaging and the expected shelf life. While some dry products can tolerate a small leak for several weeks, fresh foods in a modified atmosphere may be much more sensitive to the same defect.
In terms of leak testing, the most important question is not only the size of the leak, but also the consequences it can have on the quality and preservation of the product.