Recycled paperboard with a barrier layer for food contact: set-off during stacking or reeling. Analytical method and preliminary results

Abstract

The use of recycled paperboard for packaging dry foods is in the interest of sustainability of resources, but in most applications, the food must be protected against contamination, such as by a functional barrier on the internal surface of the paperboard box. After application, the paperboard is usually stacked or reeled before making boxes. During this period, the food-contact surface of the barrier layer is in contact with the outer side of the paperboard, which may result in set-off and subsequent contamination of food. A method is described for the determination of this path of migration, based on the taped format also used for the measurement of the barrier efficiency. Recycled paperboard containing the three surrogate substances n-heptadecane, 4-methyl benzophenone and dipropyl phthalate was taped to the food-contact side of the barrier layer. Pressure onto the test packs did not seem to be a relevant parameter. After periods of interest, a piece of the paperboard with the barrier layer was extracted and analysed for the surrogate substances. Another piece may be brought into contact with silicone paper to simulate the transfer to food. After 2 weeks at 60°C (simulating about 1 year at 25°C), set-off and the transfer to the silicone paper exceeded 1% for all barrier materials tested, but after 6 weeks at 40°C (around half a year at 25°C), set-off remained below 1% for all barrier layers except a multilayer with polyethylene on the food-contact surface. The preliminary conclusion is that set-off should be taken seriously, but may be kept low enough to provide sufficient protection of the packed food.

The Role of Residual Contaminants and Recycling Steps on Rheological Properties of Recycled Polypropylene

“…1935/2004; 10/2011 and 282/2008 [4]; and the National Health Surveillance Agency (ANVISA) [5] in Brazil and Mercosul [6]. This concern is associated with the misuse of packaging by the consumer through contamination with, for example, pesticides, solvents and cleaning products [7][8][9][10][11]. The decontamination process or the use of a functional barrier must be employed after the recycling process to ensure that the final material is safe and thus the migration is negligible [12].…”

Migration into food from closures of boxes made of recycled paperboard with an internal functional barrier

“…After removing the donor papers, the surrogate‐loaded paperboards were stacked with alternating sides up, so that the barrier side was in contact with the barrier side of the next board. Transfer of surrogate substances from the board to the food contact side of the barrier layer was hindered by this stacking, but because of the very limited diffusion into PET previously shown in the context of set‐off experiments, 23 such transfer was expected to be low anyway. The stacks for each box design were wrapped tightly in aluminium foil and shipped to PTS.…”

“…Second, as the board is usually reeled or stacked with the outer surface in contact with the barrier‐coated surface, set‐off must be low. For instance, a layer of polyethylene on the barrier surface absorbs high amounts of substances from the outer surface of the adjacent board on the reel or stack and releases them afterwards to the food 23 . Third, damages in the barrier due to creasing, scratching and cutting may cause migration into the packed food 24,25 …”

Migration of phthalates and 2,6-diisopropylnaphthalene from cellulose food packaging

“…Taking into account the packaging material, 33% of the paper packages, 40% of the cardboard packages and 75% of the corrugated cardboard packages showed migration of phthalates. 6 The sum of the specific migration of these phthalates shall not exceed 0.3 mg kg -1 . Regarding the contaminants, the most harmful phthalate migrated was DIBP since its TDI (0.01 mg kg -1 bw per day) is lower than TDI of DEHP (0.05 mg kg -1 bw per day) and it showed the highest migration among the samples 1 to 18 evaluated at room temperature.…”

“…Therefore, the potential presence of contaminants in the recycled packaging exists. Such contaminants may migrate into food, thus resulting in risks to consumers [3][4][5][6][7] . The safety of recycled cellulose materials for use in food contact packaging depends on the toxicity and the ability of post-consumer contaminants to be absorbed by recycled fibers, then released by the packaging and ultimately absorbed by the food.…”