Ensuring the seal integrity of food & beverage packaged goods is critical to product quality control and mitigation of product recalls and returns. Quality problems can subject companies to additional costs and regulations, as well as damage to their reputation. However, traditional seal testing methods are slow, destructive in nature, and don’t provide the high-precision leak testing accuracy needed to reduce waste, meet quality requirements and increase throughput.
Modified Atmosphere Packaging (MAP)
If oxygen-bearing air can be forced out of the package and replaced with carbon dioxide, reactivity decreases drastically, and critical food ingredients retain their desirable attributes. CO2 also suppresses the growth of mold and aerobic bacteria. Everything from beer to cookies to ground meat will therefore have a longer shelf life and higher customer satisfaction, thanks to CO2.
However, MAP is only effective if the actual package itself remains intact, making leak testing critical. Traditional leak testing methods such as random underwater sampling are slow and may even ruin the package. It may sound impractical, and it is costly and time-consuming, but this sampling method consists of immersing the packages in the water while operators watch for bubbles, like looking for a leak in a flat tire. The method is destructive and increases waste as the tested units can’t be returned to the production line.
Accurate, Inline Packaging Leak Detection in Real-Time
In this Food Engineering magazine article, Jason Mitchell looks at more accurate and practical methods to detect leaks in MAP. This includes infrared laser-based leak detection systems. These systems can be installed directly on the production line. Slight pressure is exerted on the package using a roller and this causes gas to be released if there is a leak. These compact detection units, including Emerson’s Rosemount CT4215 Packaging Leak Detection System, can detect and quantify carbon dioxide, even in trace amounts, taking advantage of carbon dioxide’s ability to absorb specific wavelengths of infrared light. Packages pass through a short tunnel over a conveyor, where a Quantum Cascade Laser-based detector is positioned to detect leaks from pinholes smaller than 3.0 mm.
A vacuum pump in the system draws air at a constant rate through the arch and pulls it through the QCL analyzer element. The laser source pulses on for less than 1 millisecond, allowing more than one laser to be used at effectively the same time. These fast pulses are called “chirps.” The smallest whiff of carbon dioxide can be detected in a few milliseconds by the analyzer as the package passes by, identifying a leak. The control system responds by triggering the rejection mechanism to push the leaking package off the conveyor, timed to coincide with the conveyor speed.
Quality Assurance for a Variety of Package Types