Detection of seal contamination in heat sealed food packaging based on active infrared thermography

Abstract

In the food industry packaging is often applied to protect the product from the environment, assuring quality and safety throughout shelf life if properly performed. Packaging quality depends on the material used and the closure (seal). The material is selected based on the specific needs of the food product to be wrapped. However, proper closure of the package is often harder to achieve. One problem possibly jeopardizing seal quality is the presence of food particles between the seal. Seal contamination can cause a decreased seal strength and thus an increased packaging failure risk. It can also trigger the formation of microchannels through which air and microorganisms can enter and spoil the enclosed food. Therefore, early detection and removal of seal-contaminated packages from the production chain is essential. In this work, a pulsed-type active thermography method using the heat of the sealing bars as an excitation source was studied for detecting seal contamination. The cooling profile of contaminated seals was recorded. The detection performance of four processing methods (based on a single frame, a fit of the cooling profile, pulsed phase thermography and a matched filter) was compared. High resolution digital images served as a reference to quantify contamination. The lowest detection limit (equivalent diameter of 0.63 mm) and the lowest processing time (0.42 s per sample) were obtained for the method based on a single frame. Presumably, practical limitations in the recording stage prevented the added value of active thermography to be fully reflected in this application.

Understanding the factors affecting the seal integrity in heat sealed flexible food packages: A review

“…On the other hand, advanced techniques such as thermal, ultrasonic, infrared or X-ray imaging require more development. 82,83 The main study directions to achieve and ensure sufficient sealing considering the industrial requirements were summarized in this section. In conclusion, there is a lot of room for improvement of sealing processes of flexible packagings.…”

Active Infrared Thermography for Seal Contamination Detection in Heat-Sealed Food Packaging

“…As mentioned in [24], no clear phase contrast between defective and background pixels was found. The amplitude images at the lowest frequency bin (f = 0.059 Hz) provided the highest contrast between contaminants and background.…”

“…High resolution digital images served as a reference to quantify seal contamination. The work described in this paper departs from the basis laid in [24].…”