Leak detection and package integrity testing for food safety: What types of products should be tested?
Package integrity testing can be done on a wide range of products that require special attention in the integrity testing phase before they are sold. This is necessary because of the characteristics of the product or of the consumers who will consume them. They include:
- Cans: cans are commonly used in the food industry and testing is done on all foods stored in metal containers (two-piece can), such as tuna, vegetables, tomato sauce and so on.
- Oil cans or other metal containers (three-piece can)
- Aerosol cans (both empty and filled)
- Energy drinks and other beverages
- Baby food and products for children
- Coffee pods
- Ready meals, food trays
- Pet food
- Milk and dairy products
Basically, all products contained in rigid containers such as cans can be tested. So can foods sold in containers closed with a heat-sealed lid, like many ready-to-eat pre-cooked products or other common foods such as yoghurt, milk, baby foods and so on.
Test types and methods used
When testing food product packaging, we check that the container has no cracks, holes or micro-holes that would prevent it from effectively performing its function as a barrier to the external environment.
We can use different types of tests to do this, depending on the type of packaging and the level of performance required on the production line. Remember that the pace of production is generally very rapid in the food industry, so tests that do not slow down production speed are needed, as plant efficiency would be compromised. The most efficient methods in this regard are:
- Vacuum Decay Method (VDM): this technology uses a vacuum to detect leaks in a sealed container without destroying or damaging the product in any way. Once a product has been tested and found to comply with standards, it can be re-introduced on the line and ultimately be sold. The product is inserted in a test chamber, inside which a vacuum is created. Pressure variation after a given time interval is analysed to identify the presence and extent of leaks.
To reduce the time required for testing, we can insert only the part of the container at greatest risk in the test chamber. For food stored in bottles, for example, only the cap would be tested. This means that we can use smaller test chambers, so a vacuum can be created more quickly and pressure values detected more rapidly.
- Lid deflection: this testing method is especially suitable for testing containers with plastic or aluminium films that are heat sealed to the container. In this case, special sensors or optical laser detectors check the proper positioning of the protective membrane. This type of test is particularly useful in the food sector, because the container’s integrity can be checked without the product actually being touched, providing excellent guarantees in terms of limiting contamination.