Characterisation of food contact non-stick coatings containing TiO₂ nanoparticles and study of their possible release into food

Abstract

Novel nanoparticles containing non-stick coatings have been developed for food contact applications such as frying pans. Possible release of nanoparticles from such coatings into food is not known. In this paper, the characterisation of commercially available non-stick coatings was performed by use of FTIR, electron and optical microscopy, EDXS and XRD analysis. Characterisation revealed that the coatings contained micron- and nanosized rutile TiO particles, and quartz SiO embedded in a silicone polymer matrix. In order to estimate possible migration of TiO nanoparticles from coatings into food, migration tests into simulants (deionised water, 3% acetic acid and 5 g l citric acid) were performed (2 h at 100°C), and thermal and mechanical degradation of the matrix was studied. Simulants were analysed by ICP-MS after ultrafiltration and by microwave-assisted digestion. The concentration of titanium-containing particles that migrated into simulants was up to 861 µg l (147 µg dm). Titanium was present in simulants in ionic form as well. The presence of TiO nanoparticles in 3% acetic acid was confirmed by SEM-EDXS analysis. Thermal stability study (TG/DSC MS analysis) did not show degradation of the matrix under foreseeable conditions of use, but mechanical degradation studies (scratch and tribological testing) showed possible release (microgram quantities per punched sample) of titanium-containing nanoparticles. The matrix degradation results were confirmed by observations of the morphology of the same type of coatings actually used for food preparation. Dissolution from the surface and matrix degradation can both contribute to nanoparticles release from this type of non-stick food contact coatings.

Possible Adverse Effects of Food Additive E171 (Titanium Dioxide) Related to Particle Specific Human Toxicity, Including the Immune System

“…The accidental ingestion of toothpaste, while brushing teeth is another major source of E171 intake, that can result in an exposure of 0.15 to 3.9 mg/day, when 10% of toothpaste is ingested [50]. Additional release of TiO 2 particles (70-200 nm) from food packaging materials or food-related products, such as frying pans, may also contribute to TiO 2 ingestion [55]. The focus of oral TiO 2 exposure estimation should potentially be extended from the food additive E171 to personal care products, packaging, and coating of household items [28,33,55].…”

“…Additional release of TiO 2 particles (70-200 nm) from food packaging materials or food-related products, such as frying pans, may also contribute to TiO 2 ingestion [55]. The focus of oral TiO 2 exposure estimation should potentially be extended from the food additive E171 to personal care products, packaging, and coating of household items [28,33,55]. Daily dietary intake of E171 can reach several hundred milligrams, of which at least 10-40% are in the form of TiO 2 nanoparticles.…”

Impact of an Artificial Digestion Procedure on Aluminum-Containing Nanomaterials

“…The use of aluminum-containing packaging, consumer products and kitchenware has increased 10 , as well as the use of chemical solvents, leaches and acids. Several metal species are present in a significant amount in food as nano-scaled particles [11][12] and migrate into food from packaging material [13][14][15] . Like other orally ingested metals, aluminum nanoparticles overcome the different compartments of the human digestion tract.…”

Investigations into the Potential Abrasive Release of Nanomaterials due to Material Stress Conditions—Part B: Silver, Titanium Nitride, and Laponite Nanoparticles in Plastic Composites

“…However, no release of isolated nanoparticles was found but abrasion of polymer that contained the nanomaterial solely. In another study Golja et al [20] used an indirect measurement approach based on total Ti (ionic and particulate) without and with ultrafiltration to conclude from the difference on the potential release of particulate TiO 2 material. They report a correlation between mechanical stressing and release of nanomaterials [20].…”

“…In another study Golja et al [20] used an indirect measurement approach based on total Ti (ionic and particulate) without and with ultrafiltration to conclude from the difference on the potential release of particulate TiO 2 material. They report a correlation between mechanical stressing and release of nanomaterials [20]. In the respective study scratching of the surface of the pan coating led to higher release levels of titanium dioxide than test samples that were not stressed mechanically.…”