Study assesses potential impact of inks on packaged foodstuffs

Véronique Vernat, Janine Abjean, Murielle Blanc, Stéphane Papilloud and David Baudraz report on a research and development collaboration between an ink supplier and end user on the potential effects of ink on packed foods.

In September2000, a project was initiated in collaboration between food company Groupe Danone and ink producer SICPA in order to have a better knowledge of problems end-users of the food industry have to face.

The main purpose was to implement relevant tools and procedures to help anticipate and monitor critical aspects, such as food safety and sensory issues.

After defining the axes of the project, mainly focused on ink materials likely to migrate and to affect toxicological or organoleptic properties of packed foodstuffs, tests and studies were carried out by the two companies involved. The results were then compared and correlated in order to prepare ground for specifications on raw materials to be used and to determine the analysis procedures to be adopted.

Groupe Danone is a major player in the food sector, producing fresh dairy products, packaged waters, cereal biscuits and snacks.

Danone Vitapole, located in Palaiseau, France, concentrates research and development activities of the Danone Group. Equipped with high-performance tools and facilities, it has recently been set up in order to guarantee that products developed, bring health, pleasure and well-being to consumers.

Sensory behaviours

For SICPA, this collaboration with Danone Vitapole R&D centre was an opportunity to work with a key player of the food industry and to gain expertise in areas and issues closely monitored for their critical aspects by end-users: migration, sensory behaviours, suspicious molecules such as plasticisers and breakdown products. The purpose was also to share SICPA's knowledge with Danone of ink composition, ink behaviour and end-uses, in order to provide them with valuable HSE data and analytical procedures. Finally, the objective was to compare and correlate the results obtained separately by both companies, so as to provide Danone with data enabling to define specifications of inks suitable for the applications and needs of the snack and biscuit industry.

Packaging types

The first step was to check packaging types and structures commonly used on the biscuit market (type of substrates, type of inks, etc) and to select the most representative packaging system for the study.

Then, it was necessary to choose the SICPA inks required to print the selected substrate, so as to prepare printing samples to be tested and to clearly identify components from these inks to be later quantified for their potential risk or sensory impact.

Thus, after the list of substances to be supervised was drawn up, the starting materials to be analysed had to be chosen: p SICPA would work on printed samples prepared for the study, p Danone would work on food contained in the standard packaging system selected for the project ­ in this case, biscuits.

To conduct the tests, each company had to identify the most suitable analytical methods and then define the analytical protocols.

After studying carefully methods recommended by literature, it was decided that both companies will rely on the GC/MS technique as well as migration tests using food simulants.

Parameters of the study

What follows is a list of the substances to be quantified p Propanoic acid. p 2.4 pentadione. p DEHA (SML 18mg/kgfood). p DEHP (SML 3mg/kgfood). p 2-ethyl hexanol. p Erucamide.

Propanoic acid and 2,4pentadione are generated by thermal degradation from respectively zirconium propionate and titanium acetylacetonate, both used as adhesion promoters in ink formulations. They are known for their negative impact on food sensory properties.

DEHA and DEHP are used as plasticisers and are strictly regulated with specific migration limits. Although DEHP is forbidden by the European legislation, it can sometimes be found in solvent-based inks.

These inks are usually dedicated to non-food applications, but components and additives can be transferred to food packaging inks in the printer's premises after bad cleaning or accidental mixing.

2-ethyl hexanol is the breakdown product of both DEHA and DEHP and is suspected to deteriorate sensory properties of foodstuffs.

Erucamide, a fatty amide, is used as a slipping agent and could taint food.

Printed samples were prepared with SICPA inks. It was decided to work on two different ink types: an old generation ink, which is moreover not recommended for food applications, and an ink from solvent-based SICPA series recently developed.

These two inks are representative of products available on the market: inks as they can be supplied by companies not committed to develop products complying with stringent HSE requirements as well as inks developed by manufacturers deeply involved in HSE programmes and with an advanced knowledge of HSE issues.

Substrate: Plastic film (white OPP).

Food samples from Danone: Biscuits (Petit Beurre LU).

Analytical methods

The study was based on migration tests. For these tests, packaging or printed sample pieces were placed in presence of food or food simulants in an atmosphere reproducing or simulating the real market conditions. After a specified period, analysis were carried out in order to estimate or measure levels of studied molecules that were released.

Both partners worked with GC-MS. Volatile compounds have been measured by head space. Non volatile compounds have been quantified by migration of substances into simulants, concentration and injection of the liquid phase in GC-MS system.

Danone had to develop a specific extraction method of substances to be tested, directly from the biscuits. Problems have been experienced due to fatty materials in the biscuits, causing distortion of results.

After many adjustments, a method was finally found to be successful and reliable but solely for the study of DEHA and euricamide contents, which tend to be the most sensitive substances for Danone.

Results and main conclusions

Two series of measurements carried out at the beginning and at the end of a period of four/five months provide a good correlation between the measured results and the ink formulation rates.

Fortunately, results show that migration is lower in real samples than in simulants.

Results show that erucamide is mainly brought by the film and for a small part by the ink. Therefore, whether the biscuit is placed in contact with the film alone or with the printed film, the same erucamide content is approximately found in biscuits. It can be concluded that the effect of ink on the global content of erucamide is negligible. On the contrary, DEHA clearly originates from the inks.

The measured values leave a safety margin compared to the limit values recommended by the regulations when those exist and never exceed the maximum values in food.

For DEHA, which was shown to migrate mainly from the ink, correlation can be done clearly and a safety factor of 3.5 is observed.

However, the simulant used (EtOH95percent) is likely to be destructive and to distort results because of permeation. Therefore, some results may not represent the real-life situation.

Organoleptic studies have shown that the degradation of sensory properties follows the increase in the concentration of migrant substances. However increases are not significant and have to be considered as a global trend.

Conclusion

The success of this project lies in the very active partnership which was established between the two companies.

This collaboration was an opportunity for both SICPA and Groupe Danone to improve knowledge of analytical methods and protocols from scientific literature and to discuss regularly the relevancy of the results of the study.

This project was focused on the exchange of views on the solutions most adapted to limit or to eliminate the negative impact of suspicious molecules and molecules with specific migration limits on sensory properties of the packed product.

Well-known as a supplier that closely follows HSE standards and regulations, SICPA was able to take advantage of the know-how of Danone in the field of migration.

The company was able to demonstrate its expertise in the field of migration and sensory analysis gives the guarantee that SICPA's inks always meet strictly tested and defined requirements.

Véronique Vernat, Janine Abjean and Murielle Blanc are with Danone Vitapole, Palaiseau France. www.danonevitapole.com. Stéphane Papilloud and David Baudraz are with SICPA Group Analytical Laboratory, SICPA Management SA, Prilly, Switzerland. www.sicpa.com