Why packaging inks are crucial for consumer safety

Packaging is an essential tool to make products stand out from the competition. Beyond the shelf appeal, packaging also provides protection to the contents from physical, chemical and microbiological hazards. However, a lesser-known fact is that the same packaging material could also be a source of chemical contaminants, and hence, may impact food safety as well as food quality. Among the different components of packaging material, packaging inks play a critical role as they might hamper product and consumer safety.

Each packaging ink is a mixture of different chemicals and some of these chemicals might be harmful with the potential to migrate to the foodstuff when getting in contact. In terms of risk, the chemicals could be toxic, carcinogenic, mutagenic, repro-toxic and even endocrine disruptors. The chemical contaminants from the packaging inks can get transferred to the foodstuff by a process called migration.

Over the last two decades, a number of scientific papers have been published, revealing the migration potential of substances from the printed matter. However, the first big scandal that brought the subject alive was about the findings of isopropyl thioxanthone (ITX, a low molecular photo initiator used in UV inks) in baby milk and other liquid foodstuffs all over Europe, resulting in a product recall in the year 2005. The food scandal alerted the packaging chain about the linkage between packaging inks and food safety.

Consequently, the authorities issued strict regulations for the application of printing inks as well as general food control measures.

Food safety and migration

Migration can be described as a transfer of chemical contaminants from the food packaging material to the food, thereby making it unsafe. Migrants are substances which, due to their chemical characteristics and molecular size, move from a printed layer into the packed food. There are different types of migration, which are as follows:

Set-off migration

Migrations can happen from one layer to another, such as a surface printed layer to the non-printed food-contact surface, which is later brought into contact with food. If these are in direct or close contact, like in a reel or a stack after printing, set-off migration can easily occur due to the pressure existing in the reel or stack.

Diffusion migration

Small and mobile molecules can easily penetrate and diffuse across packaging material layers.

This can occur even if the printed material has not yet been converted into a food package and filled with food, or later when the printed package is filled with food and the food starts to extract the migrants from the packaging material.

Gas-phase migration

Migration can also happen from a cardboard (the releasing reservoir) via the gas phase within the pack, to end up in food which acts as the recipient reservoir (gas phase migration). This can, for example, occur with migrants like mineral oils or some UV photo-initiators that might not be generally known as being volatile, such as organic solvents.

This process of migration is influenced by several factors like the physico-chemical properties of the migrant, of packaging material and of the food product; the storage time and temperature, and the size of packaging in proportion to foodstuff volume.

Concept of safe, compliant and migration optimised inks

Compliance in packaging safety needs to be based on these three pillars — legal requirements; brand owner requirements and self-commitments.

Each supply chain partner (including the ink manufacturer, adhesive manufacturer and substrate manufacturer) needs to be aware of the legal requirements (relevant for a particular region) for their component of the packaging structure and must build systematic processes to ensure delivery of consistent and safe products. If the packaging material needs to be exported, the legal requirements of the importing country must also be given due consideration.

Brand owners, with their global footprints, sometimes have their own specific requirements for packaging safety beyond the legal requirements of the countries (especially developing countries like India). Each supply chain partner needs to make themselves aware of such requirements and upgrade their products to comply with such norms, in order to offer the same level of consumer safety across all regions.   

Each supply chain partner is responsible for their own products and formulations. Hence, it becomes the ethical responsibility of supply chain partners to deliver safe products (with only safe chemicals in their formulations) and also update the authorities and brand owners on such initiatives to benefit the society at large.

Compliance can never be achieved through an isolated approach since each packaging structure is a mixture of different components (including substrate, ink and varnishes), and hence, there should be an open and transparent communication across the supply chain on the requirements, as well as on the risk assessment of the individual components of the packaging structure.

Migration-optimised inks  

In the Indian market, there is a demand for the so-called non-toluene (NT) inks, non-toluene non-ketone (NTNK) inks, mineral oil-free inks, etc. However, safe inks should not be misled with such terminology adopted by the market, as such inks may not be safe.

Each printing ink consists of four general components — binder/resin, solvent, additives and pigment/colorant. By excluding a solvent like toluene, ketone, mineral oils, etc, one cannot assume and be assured that the inks are safe.

Safe inks (or migration-optimised inks) are inks with careful selection of raw materials in all four categories, so that none of the components of the printing ink formulations impact consumer safety.

Hence, the next time one is looking for safe inks, he/she should ask for migration-optimised inks.

Good manufacturing practices

Packaging materials and articles shall be manufactured in compliance with good manufacturing practices (GMPs), 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 or bring about a deterioration in the organoleptic characteristics. GMPs should be exercised across the supply chain if packaging safety needs to be ensured.

There are several parameters and conditions that need to be controlled at the converters’ shop floor to make sure that the final intended article is safe. Even if one has procured the safe raw materials (such as substrate, inks, adhesives etc.), if they are not processed in the right manner, the final intended article would never be food safe. 

For example, in the case of solvent-based inks, solvent drying is an essential part of the manufacturing process of the final packaging material, which is carried out at the converter’s end. In case solvent drying is not handled appropriately at the converter shop floor, retained solvent in the final packaging material can migrate into the product, thereby not only endangering human health, but also impacting the organoleptic properties of the product.

Converters also need to ensure that cross-contamination at the facility is well taken care of and there are adequate validated controls to ensure that.

Regulatory update

There is a lot of scientific literature available on packaging contaminants as well as packaging safety. However, recently the Food Safety and Standard Authority of India has taken concrete steps to ensure consumer safety by raising the bar of packaging safety. FSSAI has enforced Food Safety and Standard (Packaging) regulations, 2018 from 1 July 2019. The standard clearly indicates that a packaging material is to be considered food grade when the material is made of substances which are safe and suitable for their intended use and shall not endanger human health or result in unacceptable change in the composition of the food or organoleptic characteristics. 

FSSAI also mandates the brand owners to use inks for their packaging material which are complying to IS 15495. IS 15495 is a standard created by the Bureau of Indian Standards and has recently been revised. IS 15495 in its current form reiterates the concept of food grade packaging materials where packaging material shall be so manufactured that under normal or foreseeable condition of use, they shall not transfer their constituents to the food in quantities, which may endanger human health, cause a deterioration in the organoleptic characteristics or unacceptable change in nature, substance and/or quality of food. However, BIS has now made amendments to the standard with major highlights as follows: 

• Sum of concentration levels of lead, cadmium, mercury and chromium (VI) shall not exceed 100 ppm for printing inks. 

• Addition of toluene, DBP, DiNP, titanium acetylacetonate to the existing Annex A, which lists the materials and substances that needs to be excluded from printing ink formulations. 

As per the amendments made, toluene will no longer be allowed to be used as a solvent in printing inks intended for food applications thus ensuring safe packaging for consumers. Phasing out toluene will not happen in an instant, but it is a step in the right direction.

(Jatin Takkar is the senior manager – product safety and regulatory at Siegwerk India. He is a food technologist and has worked in the domain of food safety and regulatory compliances with various MNCs, such as Nestle and Kraft Heinz before settling in at Siegwerk India. At Siegwerk, Takkar is responsible for the product safety and regulatory segment and ensures the formulation of compliant inks which are demonstrated by systems and supported by documentation. He is also there to support the entire market on product safety and compliances.)