Food safety – Sealing: The weak link

Sealing is a critical control point in food security that is sometimes difficult to master, so full inspection via vision systems tends to be required on production lines

A vital critical point

Tray or bag packaging conditioned in a modified atmosphere is becoming widespread in our daily life in response to our requirements for freshness, extended shelf life or simply practical considerations. The sealing of this packaging guarantees that it is hermetically sealed from the outside environment, irrespective of the technology used to create it. This sealing is both an essential safeguard against health risks, but also a link exposed to particular stresses throughout the product’s life cycle (crating, transport, and shelving). The slightest sealing defect is thus totally excluded as it could impair the primary function of the packaging, namely to protect the food from the plant to the plate.

A complex process to control

Unfortunately, industrial control of this critical point is still relatively complex. Sealing defects generated in the sealing zone can actually have several causes: the main ones being contamination of the sealing surface during filling and sealing tool drift, which generates folds, bubbles or partial lack of sealant. These defects expose manufacturers to a dual risk: economic risk concerning the scrapping of whole batches if the process is not continuously controlled, but also a brand image risk related to the possible marketing of contaminated or badly preserved products.
Towards an «control all» requirement for the consumer and improved control over the process for the manufacturer. To eradicate these risks, manufacturers must make their control procedures more reliable but also save and store their data to ensure perfect traceability for the product. These requirements are driving the development of full control of the manufactured products that only vision inspection systems can perform at satisfactory rates. However, manufacturers will certainly not be happy with post-control of their products for very long and will be looking for solutions to improve control of their sealing process. This is why the vision inspection systems must go even further in the future and interact upstream with the machines to enable real time self-checking of the sealing tool.

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