The importance of leak test food packaging to waste reduction

There are many ways in which food waste is produced. For example, fresh produce that never leaves the farm where they are cultivated, foods that are lost or damaged during transportation, foods that exceed their shelf life or foods that are thrown away from hospitality sectors or households. The actions to process and manage these wastes significantly impact the country's economy and the environment.

According to the Australian Department of Agriculture, Water and the Environment, food waste costs the Australian economy approximately $36.6 billion annually. It contributes to around 3% of the total annual greenhouse gas emissions. Farmers also use an equivalent of 2600 gigalitres of water and more than 25 million hectares of land to grow the food that ultimately gets wasted.

Ensuring the seal integrity and leak-free packaging plays a critical role in minimizing food waste by preventing the ingress of contaminants such as oxygen, moisture or microorganisms which can adversely affect the product shelf life. Manufacturers have developed the optimum packaging technique by choosing suitable materials and establishing appropriate sealing parameters.

Modified atmosphere packaging (MAP) is a technique that uses chemically inert gases to fill the package as they can keep the product fresh for longer. It is a highly effective method to preserve food quality, but manufacturers must ensure that packages are in perfect condition when they leave the production line. Therefore, they will also need a reliable method to check if the containers are airtight.

Packaging leaks can arise from film defects or improper sealing. The leaks may present themselves as simple holes or permeable, porous regions that are difficult to identify visually. However, food manufacturers also need to adjust the degree of sealing to keep the margin at a profitable level. They need to specify the acceptable leak rate and determine the point at which the packaging no longer passes the leak test.

Based on the above criteria, manufacturers choose the leak testing system to be integrated into their production process. Selecting the suitable method will depend on the types of packaging to be tested, the need to identify the leak location and whether the packaging contains gases. Food manufacturers must use reliable leak testers to reduce food waste and prevent product recalls.

Types of Packaging Leak Testers

Underwater / Bubble Leak Testers

A bubble leak tester is a widely popular method for detecting leaks in packaging by submerging it underwater. Leaks are determined by observing the visible bubbles which arise from the leak location. This method is unreliable for detecting small leaks and prone to error as it relies on the operators to make the correct judgment.

Pressure Decay Leak Testers

This innovative test method involves placing a package into the test chamber and evacuating the air inside the chamber to create a vacuum. The pressure decay inside the vacuum chamber is measured using a highly sensitive differential pressure transmitter. It allows the calculation of leak rate which is used to determine whether the packages pass the standard test. As leak is quantitatively determined, it has the advantage of being independent of operators and hence the tester can safely detect coarse or micro leaks.

Principle of Pressure Decay Leak Test

The pressure decay leak test is initiated by putting the test package into the closely-fitted chamber. Then, operators start the vacuum pump to remove the air inside the chamber, creating a vacuum environment. Vacuum evacuation is stopped once the chamber reaches the desired vacuum level. Under the normal operating condition, the pressure level inside the testing chamber will slowly return to the atmospheric pressure.

A leak in the packages is identified based on the rate of pressure decay towards the atmospheric pressure. The operators must work out the maximum allowable leak as a passing standard. This standard will differ for different types of packaging and will depend on the maximum stress they expect the package to experience throughout the supply chain process.

Choosing between pressure decay vs. underwater leak testers

Both underwater and pressure decay leak testers have been used for packaging leak testing applications in the manufacturing environment. In the past, water bath leak testers are more widely used due to their simplicity. It does not require any training to operate the system and interpret leaks. This trend has gradually reversed as the modern manufacturing environment now focuses its requirement on increasing automation, quality control and data traceability.

Leaks identified through underwater leak testers are subjective and manually observed. Therefore, there is a limited capability to interface this with other industrial communication systems. With the pressure decay leak testers from Bestech Australia, the quantitative test results are stored in the system's internal memory and can be easily retrieved via USB or Ethernet.

Packages that pass the pressure decay leak testers can be returned to the production line and further processed. This is in contrast with the underwater testers as packages must be discarded regardless of their test results. Not only does this accumulate production waste, but the manufacturers also cope with the significant financial loss as they test more products, especially if the products are high-value items such as milk powder.

However, this does not mean that underwater leak testers are outdated. This easy-to-use system has the capability to pinpoint the leak location precisely, which allows the operators to identify problematic areas in their packaging machines and fix them.

Leak testing configuration in Food manufacturing

For manufacturers that choose to adopt packaging leak testing in their production environment, they can reap substantial benefits through minimising production waste which improves their manufacturing efficiency and revenue.

Through regular leak testing, manufacturers can prevent defective packages from making their way to the market. This not only prevents the costly product recall but also prevents additional production waste as the recalled products will be dumped. In addition, leak testing also allows the operators to quickly identify the problematic sealing machine and schedule a maintenance program before it escalates.

Bestech leak testing systems are designed with a robust stainless steel housing to suit the production environment. Our engineers have suggested using both leak testing systems for maximum efficiency. The pressure decay leak testers can be employed in every production line as the primary leak testers since they can offer some degree of automation and are more reliable. For packaging that fails the primary leak test, operators can plunge the failed packages into the underwater leak tester to identify the source of leaks.

Concluding Remarks

Every manufacturing process generates production waste either as tangible or intangible products. Tangible waste such as damaged packaging can be easily prevented by early identification of potential issues in the sealing machine which can be done by leak testing. Manufacturers can also maximize production output by utilising systems that do not require them to throw the products after each test.