Food and beverage packaging must adhere to a very detailed set of safety standards, down to the ink on the label and the glue that brings it all together.

Ensuring packaging ink and coatings do not migrate to the food enclosed within the package is crucial to supplying clean, food-safe packaging. Minimizing risk to the consumer and ensuring that packaging is compliant with global regulations and food packaging standards — as well brand standards — is increasingly complex.

Printing and ink

Some of the most commonly marked pieces of information on packaged foods is date coding and traceability information, including barcodes, expiration dates, lot numbers and batch coding. This information is critical for being able to track product, quality control and aiding in the sale of the products. Getting this information onto each of the packages is a necessary and vital part of the product’s life cycle.

The nature of food packaging itself, however, can present challenges to direct part marking methods. Food packaging is often flexible, so products that don’t have ridged or flat surfaces can make the application somewhat tricky.

Some products will also be exposed to damp or wet environments. Products that are frozen, for instance, will need to be able to retain their barcode markings even if they become slightly damp from temperature changes.

Packaging ink can infiltrate food items through ink migration, which is when ink substances transfer from the packaging material into the food. Apart from contaminating food, ink migration can change its flavor and odor. It will compromise food safety and tarnish a brand’s reputation.

For example, Swiss food manufacturer Nestlé had to recall baby milk products from five European countries in 2005 because of the type of ink used. The recall was announced after food safety officials in Italy discovered that a batch of milk due to expire in September 2006 had been contaminated by a chemical that leaked from the packaging.

Food-safe inks have proper surface tension for imprinting, fast drying time, smear resistance and suitable viscosity. They contain safe chemicals for human consumption and meet specific regulatory guidelines. The purpose of food-grade ink is to ensure that food is free from toxins, harmful metals and dangerous chemicals.

Glycerin is one of the primary ingredients in food-grade ink and acts as a co-solvent. Edible inks also contain water, traces of food-grade dye and food glycerol. These inks must also undergo a hygiene manufacturing process to avoid contamination with non-food-grade substances.

Printing inks are complex mixtures that are typically made up of colorants, binders, solvents and additives, such as plasticizers and antioxidants.

There are no regulations that clear specific ink formulations for use on food packaging; rather, some common components of inks may be cleared under volume 21 of the Code of Federal Regulations (CFR), including Section 178.3297 (“Colorants for polymers”) or, if used in paper applications, under CFR Section 176.170 (“Components of paper and paperboard in contact with aqueous and fatty foods”). Colorants also may be permitted for their intended use under a Threshold of Regulation exemption, a prior sanction, or a Food Contact Notification (FCN).

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In-mold labeling

MCC Verstraete’s specialty is in-mold labeling (IML). The company sees it as a growing technology, as the dairy industry becomes more familiar with the option, said Mathieu Nieuwenhuyse, general manager for the Americas region. The company’s technology continues to expand with improved barrier capabilities and using invisible blue inks for detection purposes on the packaging.

“NextCycle IML makes it easier in a mechanical recycling stream to actually recycle the packaging to new food grade packaging,” Nieuwenhuyse said. “This is an important enabler that gives us a strong belief that NextCycle will be the IML of the future.”

When the NextCycle IML labels are combined with the company’s SealPPeel die-cut lidding and digital watermarks, it becomes the company’s most sustainable packaging offerings to date. The NextCycle IML technology was reverse-engineered by looking at the mechanical sorting streams in the European market. The labels release from the packaging in a mechanical sorting process, leaving behind a pure polypropylene residue.

Adhesives and glues

When direct on-pack labeling isn’t possible, labels are attached using approved adhesives.

The global market for packaging adhesives reached $16,560.21 million in 2021 and is expected to grow at a CAGR of 5.63% from 2022-2027. Food packaging adhesives are a significant contributor to the overall market growth.

The primary function of food-safe glue is to prevent contamination of food products. It does this by creating a secure barrier between the food and the surrounding environment, thus inhibiting the growth of bacteria or other harmful microbes.

In some usages, food-safe adhesives are used to maintain the freshness and quality of food items. They protect the food against exposure to air, moisture and temperature fluctuations that could lead to spoilage or degradation of quality.

The US Food and Drug Administration (FDA) regulates the use of adhesives for food packaging. According to the FDA, food-safe adhesives are classified as a food contact substance “intended for use as a component of materials used in the manufacturing, packing, packaging, transportation or holding of food that is not intended to have a technical effect in food.”

Since adhesives used to package food can come into indirect contact with it, the glue needs to pass stricter safety criteria. Adhesive manufacturers are supposed to closely follow the rules for raw materials in FDA, Section 175.300, and the formulation rules stated in Section 175.105.

Section 175.105 also needs manufacturers to abide by the rules on the ways adhesives can be used for packaging and the kind of physical contact that’s allowed. As per Section 175.105, packaging manufacturers of finished food should either make sure that adhesives are segregated from food with the help of a barrier or with the extra limitations depending on food type. For dry foods, the amount of adhesive in contact with the food must be within the limits stated under the Current Good Manufacturing Practices (CGMPs). For fatty or aqueous foods, contact with adhesives can’t exceed at the seams and edges of the packaging laminate that comes with the CGMP parameters.

The types of food-grade adhesive were large, less than a couple of years ago, categorized into two main groups: cold set adhesives and hot set adhesives. Today that is no longer the case. Advances in food packaging and food preparation have opened the field to new tech, allowing vogue food-safe adhesives to enter the scene. In many cases, these adhesives are partly inspired by those two categories and offshoots of them.

Utilization of food-safe glue helps food handling and production businesses comply with food safety regulations. It aids in passing health inspections and avoiding legal complications or penalties.

Through these roles, food-safe glues and adhesives play an essential part in ensuring the safety, quality and visual appeal of food while also supporting the operations of the food industry.