Everything you need to know about food packaging

The glossary contains valuable food safety definitions of our adhesive experts stored in a central place. Browse through our extensive knowledge center and deepen your understanding of crucial food packaging topics, for example migration, ALARA, food contact legislation or quality standards.

ALARA is the abbreviation for "as low as reasonable achievable". Working according to the ALARA principle in terms of food contact means that all possible migrants should be reduced to the minimum level necessary to achieve the intended technical effect.

The Henkel analytical center in Düsseldorf offers its analytical services to all business units of Henkel, as well as to external customers. It supports Henkel products throughout their whole life cycle: from research via product development to production, product management, sales and technical customer service. The analytical services are as varied as the Henkel product range, from adhesives to laundry products and cosmetics. Depending on the requested information, the analytical center has all techniques available to investigate raw materials as well as finished goods, check specifications or perform failure analysis.

Antioxidants are often used in thermoplastic systems like hotmelt adhesives in order to prevent thermo-oxidative damages (degradation, skinning, discolouration) of the adhesives especially when they are in molten state. Antioxidants which are commonly used are of rather low molecular weight, e.g. phenolic antioxidants, thiosynergists or phosphites. Henkel uses, for products with possible food contact, only antioxidants which are listed in the plastic regulation (EU) No 10/2011 and in the respective FDA regulations.

Benzoates like diethyleneglycol dibenzoate, dipropyleneglycol dibenzoate and triethyleneglycol dibenzoate are often used as plasticizers.

The BfR (Bundesinstitut für Risikobewertung) is the Federal Institute for Risk Assessment in Germany that comes under the portfolio of the Federal Ministry of Food, Agriculture and Consumer Protection for all scientific aspects of consumer health protection. Their main duties are the identification of risks and the protection of health. According to the corporate BfR website, the tasks “encompass the assessment of existing and the identification of new health risks, the drawing up of recommendations on risk reduction and the communication of this process. In its assessments and recommendations, BfR is not influenced by any economic, political or social interests. It presents them in a comprehensible manner for the general public.” The BfR comes up with regularly updated recommendations of its in-house expert team, which are not laws. There are specific chapters for different product groups, for example adhesives/dispersions (BfR XIV) or polyurethanes (BfR XXVIII). The framework regulation states that - as long as there is no specific legislation in Europe, e.g. for adhesives - it is allowed to use national regulations or recommendations such as the BfR.

Find more information on the website of BfR

Boric Acid
Boric acid and borates are additives widely used in adhesives. They are used to increase viscosity and tackiness of adhesives mostly in Paper Converting and in Labeling. Boric Acid and borates have been included into the candidate list of SVHC (Substances of Very High Concern). They are classified as toxic for reproduction and are not persistent, bioaccumulative and toxic (PBT) according to the Regulation (EC) No 1272/2008. The amount of boric acid and borates used in adhesives is often much lower than the concentration limits that lead to the classification of the finish product. New categories of borate free adhesives are available.

The CLP Regulation ("Classification, Labeling and Packaging", Regulation (EC) No 1272/2008) implements the Globally Harmonised System (GHS) into the European Union. It replaces the current system contained in the Dangerous Substances Directive (67/548/EEC) and the Dangerous Preparations Directive (1999/45/EC). With this, the well-known R- & S-phrases (risk and safety phrases) and orange pictograms will be replaced by H- & P-phrases (hazard and precautionary phrases) and new diamond shaped pictograms with a red frame. Products consisting of only one substance had to be reclassified and relabelled according to the new requirements by December 1st, 2010.

CMR Substances
CMR stands for "carcinogenic, mutagenic or toxic to reproduction". Substances that have one or multiple of these properties are classified as CMR substances.

Cold Seal
Cold seals are materials that can be coated onto film substrates, where they create a layer that is not tacky like a standard pressure-sensitive adhesive but still adhesive enough to allow sealing to itself. This allows cold seals to be coated onto films which are stored as rollstock without undue blocking of the roll. In application, a flexible packaging can be formed from the film substrate and subsequently sealed around the edges using pressure alone. Unlike with more common heat sealing of flexible packages, also temperature sensitive filling goods, such as chocolate, can be packaged without damage.

The contamination of food with unintentionally added substances is a serious issue which makes it unfit for consumption and which can be a potential cause of diseases. Different types of contamination are possible: Biological contamination caused by bacteria or fungi, chemical contamination by chemical substances or contamination by foreign bodies (like hair, nails etc.). Adhesives also can be contaminated when not produced under GMP. For water-based adhesives, a biological contamination must be avoided by using the right preservatives. Chemical contamination of adhesives can occur by impurities from raw materials or by impure production equipment. A cross-contamination of products, which means a transfer of components from one formulation to the other during the production, must be excluded by working under GMP.

Decomposition Products
Decomposition products are formed during the production or when heating up an adhesive. They are considered as NIAS. The legislation demands to include also decomposition products within the risk assessment.

Decreto Ministeriale
Italian Decreto Ministeriale 21/03/73 and amendments is the Italian law regarding food safety. It establishes the hygiene requirements for packaging, container and tools intended to be used in contact with food. It has been regularly updated also to implement European legislation. It sets specific requirements for different materials, like plastic, rubber, regenerated cellulose, paper and paperboard, glass and stainless steel.

Defoamers are chemical additives that reduce and hinder the formation of foam in liquids during industrial process. There are different chemical families of defoamers: based on mineral oils, vegetable oils, and silicones. In these families, Henkel selects specific grades suitable for food packaging listed in food contact legislation.

Dual Use Materials
Dual use additives are substances used in food contact materials as additive as well as food additives or flavourings. Information about dual use additives should be reported in the SML table so that the filler of the foodstuff can make his proper risk assessment.

The EFSA (European Food Safety Authority) is continuously assessing substances for food contact materials by establishing specific migration limits. The EFSA panel on food contact materials, enzymes, flavourings and processing aids (CEF) regularly adopts scientific opinions and provides scientific advice for risk assessments.

EU Standard Cube
One kilogram of foodstuff is packed into a cube with 1 dm of edge length, which is equivalent to 6 dm² of total food contact area. Thus, 1 kg of foodstuff is assumed to be packed into 6 dm² of food contact material. This surface to volume ratio of 6 dm²/kg is a simplified approach and has to be adjusted to the real conditions of use when evaluating migration. 

Food Contact Statement
The food contact statement must provide the customers (e.g. converter, food producer etc.) with all necessary information so that they are able to make their own risk assessment. The European legislation demands to carry out risk assessments on each stage of the production:
- Raw material supplier: makes risk assessment for the material
- Henkel: makes risk assessment for the adhesive
- Converter: makes risk assessment for the final packaging
- Filler: makes risk assessment for the packaged food

Framework Regulation (EC) No 1935/2004
The Framework Regulation is a European food contact legislation. Accordingly, materials and articles shall be manufactured in compliance with Good Manufacturing Practice so that, under normal or foreseeable conditions of use, they do not transfer their constituents to food in quantities which could:
- endanger human health
- bring about an unacceptable change in the composition of the food
- bring about a deterioration in the organoleptic characteristics thereof

Good Manufacturing Practice (GMP) means the part of quality assurance which ensures that products are consistently produced and controlled to the quality standards appropriate to their intended use.

GMP Regulation (EC) No 2023/2006
According to articles 5, 6 and 7, the GMP Regulation (EC) No 2023/2006 demands the implementation of an effective and documented quality assurance system, the establishment of an quality control system including on-going monitoring as well as the documentation of specification, manufacturing formulas and processing.

HACCP is the abbreviation for "Hazard Analysis and Critical Control Point". HACCP is a preventive system to ensure the safety of food and to protect consumer health. It is a tool to assess hazards and to establish a control system focused on prevention. The HACCP principle can be applied on the whole production chain. The first step is a hazard analysis, carried out by identifying possible critical control points (CCPs). For these points, critical limits need to be defined and the system must be established to monitor the control of the CCPs. For these different CCPs, the definition of corrective actions is then necessary. The final goal is to establish a procedure in order to check whether or not the HACCP principle is effective and to document all steps of the procedure.

Heavy Metals
There are a lot of different definitions for heavy metals. Mostly, heavy metals are defined by their density, not taking into account their different levels of toxicity. Following the Römpp lexicon “Chemie”, heavy metals have a density of more than 5 g/cm³. Particularly, the important heavy metals mercury, lead, cadmium and chromium (VI) are considered very harmful metals. Arsenic is often included in this series because of its toxicity, although this element - accurately considered - is a semi-metal. A lot of heavy metals like iron, copper, tin and zinc are essential for human beings and therefore are so-called essential trace minerals. 

Latex Based Cold Seal
Conventional cold seal materials contain natural latex, due to the very unique properties that this natural polymer possesses. Latex gives good seal performance, which leads to packaging that has a very good resilience towards mechanical stress and that is resistant to bursting. However, as with all latex-based products, some precautions have to be taken because latex naturally contains by-products (e.g. proteins), which can cause allergic reactions in some people. Henkel therefore recommends no direct contact between filling good and latex-based cold seal coatings.

Low Migration
In general terms, migration describes the diffusion of molecules out of a package into the food or vice versa. This can reduce the quality of the packaged goods. Migratable substances are those which have a molecular mass of < 1000 Daltons. The lower its mass, the more easily a substance will migrate. Anyway, there is no generally accepted definition of “low migration”. For waterbased adhesives from Henkel, low migration means going beyond complying with the legal framework and limit values. We minimize the use of critical ingredients wherever we can and find ways of eliminating migratable substances altogether. 

Migration is the transfer of substances between two phases, that means from the packaging into the food and vice versa. All packaging materials and also the surrounding can contribute to migration. The lower its molecular mass, the more easily a substance will migrate. It is commonly accepted that molecules with a mass higher than 1000 Dalton need not be taken into consideration for the migration as their migration tendency is very low. Exactly defined migration tests only exist for plastics, which can not be applied to adhesives 1:1.

Migration Limits
This term denotes limit values for compounds that migrate into foodstuff, commonly given as overall migration limit (OML) and specific migration limit (SML).

Migration Test
The legislation concerning food contact materials sets a clear frame for the tests to be performed and generally focuses on the finished product. Overall migration tests to monitor the overall migration limit (OML) have no toxicological meaning, but they give a good indication about the inertness of the food contact material towards the filling good. Specific migration tests are performed to check the specific migration limits. Those SMLs are based on available toxicological data, and compliance with those SML values is crucial for the intended conditions of use.

Mineral Oils
Since 2011, mineral oil components in foodstuff are an important topic. Different analyses done by the Food Control Authority in Switzerland have shown that mineral oil compounds are present in a lot of packed food. This contamination mainly is caused in using newspapers in recycled paper and board. Mineral oil components are not well defined single chemical substances but fractions consisting of several substances.

Mineral oil hydrocarbons (MOH) mainly consist of two chemically and structurally different fractions: the “mineral oil aromatic hydrocarbons” (MOAH) and the “mineral oil saturated hydrocarbons” (MOSH). Technical mineral oil grades normally contain 15-35 % MOAH, that means the ratio of MOSH : MOAH mostly is 4:1.

The minor fraction of mineral oil hydrocarbons (MOH) encompasses so-called “mineral oil aromatic hydrocarbons” (MOAH). These are aromatic hydrocarbons which consist predominantly of 1-4 ring systems and are alkylated up to 97%. According to the German Bundesinstitut für Risikobewertung (BfR), a carcinogenic potential cannot be excluded for this fraction, mutagenicity is caused mainly for 3-7 ring aromatic systems.

The major mineral oil fraction is composed of so-called “mineral oil saturated hydrocarbons” (MOSH). These are paraffinic and naphthenic hydrocarbons with a carbon chain of 16-35 atoms. The European Food Safety Authority (EFSA) has estimated that we ingest between 0.03 and 0.3 mg saturated hydrocarbons per kilogram of body weight with our daily food. Animal experiments make the conclusion close that this mineral oil fraction may accumulate in the body, especially in lymph nodes, spleen and liver.

Non-intentionally added substances (NIAS) is a designation for all substances that are present in food packaging materials, which are not added as part of the formulation work of the suppliers. Such compounds are either - often unavoidable - impurities and reaction side products contained in films, inks and adhesives or substances that are formed in the application, e.g. when two components such as film and adhesive meet or when the packaging is exposed to the environment or the food. With today’s powerful analytics, NIAS can be detected in nearly any material, because at a level of parts per billion and smaller, impurities are unavoidable. As it is generally not feasible to avoid NIAS completely, a risk assessment of known NIAS can be performed and their level can be minimized by the application of ALARA principles.

According to Regulation (EU) No 10/2011, plastic materials and articles intended to come into contact with food shall not transfer their constituents to food simulants in quantities exceeding 10 milligrams of total constituents released per dm² of food contact surface (mg/dm²). This limit value of 10 mg/dm² is defined as overall migration limit (OML). Related to the EU standard cube (6 dm²/kg), it may also be expressed as 60 mg per kilogram of foodstuff in certain cases. Particular attention has to be paid to materials and articles intended to be brought into contact with food intended for infants and young children. In that case, the OML is defined as 60 milligrams of total of constituents released per kg of food simulant.

Primary aromatic amines (PAA) refers to a group of chemicals which share a common structural element, an amine attached to an aromatic ring. Several of these compounds are known or at least suspected human carcinogens. Their presence in food packaging has therefore to be avoided. Aromatic amines are generally not used as formulation components due to their toxicological profile. However, they can be formed from polyurethane inks and laminating adhesives as NIAS. This makes it absolutely necessary to test food packaging for the absence of PAAs if a reactive polyurethane component is used in the manufacture.

Photoinitiators are photo-reactive substances which create radicals after irradiation with UV-light. Those radicals can initiate polymerization and crosslinking reactions, e.g. in acrylic systems.

Phthalates like diisononyl phthalate, butyl phthalate or dibutyl phthalate are often used as plasticizers.

Plastic Regulation (EU) No 10/2011
The plastic regulation (so-called PIM) is a specific measure for plastics in food contact. It is not valid for adhesives and coatings. It only applies for plastic layers in multi-material-layers. Adhesives are expressly out of the scope of this regulation. The overall migration limit (OML) for all substances in a food package may not exceed 10 mg/dm² of the area in contact with the food. The plastic regulation also lists specific migration limits (SML) for individual substances that also have to be taken into account. These restrictions, which are based on toxicological data, can be considered also for the assessment of adhesives. 

PSA is the abbreviation for pressure sensitive adhesives. The term denotes adhesive that forms a bond when pressure is applied to unite the adhesive and the adherend. Neither solvents, water nor heat is needed to activate the adhesive. Pressure sensitive adhesives are used in a wide variety of industries, including the tape, label, graphics, medical and automobile market.

Residual Solvents
Solvent-based adhesives must be dried after applying. This drying step is not under Henkel’s control, but under the responsibility of its customers. So only the converter is able to say how high the content of the residual solvents in the final product is. Mostly, solvents are strongly influencing the organoleptic characteristics (smell and taste) of the food. So, the drying efficiency is very important for the suitability in food contact. 

Specific migration limits are defined for individual compounds that migrate into the foodstuff and do have a toxicological meaning. Specific migration limits are expressed in mg of substance per kg of food.

Stabilizers are additives for stabilization of physical and chemical properties of final adhesives. There are different types of stabilizers:
- Viscosity stabilizers: thickening agents or colloids, which are used for stabilization of viscosity, modification of rheology and avoid sedimentation and phasing
- UV stabilizers: additives that absorb UV radiation and/or prevent UV degradation of polymer
- Natural latex stabilizers (surfactants and/or thiuram): prevent the aging of natural rubber emulsions increasing mechanical stability

SVHC stands for "Substances of Very High Concern". For those substances it has been proposed that the future use will be subject of authorization under the REACH regulation (Regulation (EC) No 1907/2006). Indeed, it is the first step in the process to restrict the use of a substance. A substance can become an SVHC when it fulfils one of the following criteria:
- it is carcinogenic
- it is mutagenic
- it is toxic for reproduction
- it is persistent, bioaccumulative and toxic
- it is very persistent and very bioaccumulative
- there is "scientific evidence of probable serious effects to human health or the environment which give rise to an equivalent level of concern"; such substances are identified on a case-by-case basis

Swiss Ordinance
The Swiss Ordinance SR 817.023.21 is a law in Switzerland for consumer goods. It can be compared with the German “Bedarfsgegenständeverordnung”. As Switzerland is not member of the European Commission, the food contact legislation in Europe, e.g. the Framework Regulation, is not valid in Switzerland. Thus, Switzerland has to create its own food contact legislation. In most cases, Switzerland transfers the European legislation into its national law so that the restrictions for certain substances are the same in Switzerland as in the EU legislation. Annex VI of the Swiss Ordinance contains a special chapter for printing inks for food packaging, which does not exist in other European countries. If a foodstuff, which is packed and printed, is to be sold in Switzerland, the printing ink must be composed only of components listed on the positive lists of annex VI. List A in annex VI contains substances, which are toxicologically assessed and for which a restriction is fixed, list B contains substances, which are not yet evaluated, so that their limit is 10 ppm.

Synthetic Cold Seal
Due to the residual risk of allergic reactions to the natural latex contained in conventional cold seal products, a demand for cold seal materials that are not natural latex-based was created. Henkel has developed “synthetic” cold seal products, in which the natural latex has been replaced with a synthetic polymer that does not contain any proteins and therefore does not present a risk to persons sensitized to latex. Synthetic cold seals are currently mainly used for the medical packaging market where latex allergy is a very important topic.

The Toxicology group concentrates most of Henkel’s toxicological expertise in a corporate unit at Henkel Düsseldorf. In terms of UA food contact materials, toxicology is involved in case of specific questions where a lot of expertise is required to answer in-depth questions. Risk assessments always consist of two parts, a hazard assessment and an exposure assessment. First of all it must be identified whether or not a hazard is associated with the presence of a certain chemical in a food contact material. This hazard assessment is based on all available toxicological data, either from in vitro assays or in vivo tests or from human experience and epidemiological studies. For screening purposes, a computer-based structure activity relationship analysis might be performed. In order to come to a robust risk assessment, it might be necessary to close data gaps by conducting additional toxicological tests. The second aspect to consider is the potential exposure, e.g. of an end consumer of packaged food. This exposure can be estimated, e.g. based on migration testing. Once the hazard potential and the exposure have been identified, the toxicologist can conclude on the potential risk. A typical measure in that respect is the “Margin of Safety” (MoS). The MoS is a factor describing how many times the potential dose ingested by the end consumer is lower than the dose which did not cause adverse effects, e.g. in animals. If necessary, toxicology also provides toxicological support to Henkel customers in order to answer special questions or solve health related problems.

Triacetin, also named glycerol triacetate (CAS no 102-76-1) can be used as plasticizer. In Europe, this substance is allowed as food additive under the E number E 1518.

UV-curing is a crosslinking reaction with the help of UV light. Irradiation of an UV-reactive adhesive with UV light creates radicals (see photoinitiator). Those radicals initiate crosslinking reactions, e.g. in acrylic systems. A product with short polymer chains and low cohesion will become a cohesive, 3-dimensional network after this curing step.

Volatile organic compounds like residual solvents or monomers that readily evaporate from a substrate into the gas phase.

Zinc has been traditionally used in its salt (e.g. ZnCO3) or oxide form (ZnO) in casein based adhesives in order to improve water resistance. However, due to their low solubility in water, zinc compounds in powdery form are now classified as “R50-53”, i.e. “very toxic for the aquatic environment” and need to be labeled, packaged and transported accordingly. Henkel’s new range of casein adhesives does therefore not use any Zinc compounds.

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