After the ban : How to control titanium dioxide in food? |
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| K. Cheyns, R. Nkenda, S. Van Den Neucker, J. Mast |
- Abstract:
- Titanium dioxide (TiO2) is applied in food as a white pigment and listed as food additive E 171. EFSA's opinion [1] states that it is not certain that its use in food is safe because it may be genotoxic. Hence, the European Commission no longer allows E 171 [2]. Consequently, authorities need analytical methods to control the absence of E 171. Because most Ti occurs in food as TiO2, screening can be realized by analyzing the total Ti content as a measure (proxy) for TiO2. This study examined whether the concentrations of total Ti are (much) larger in food products containing E 171 than in products without E 171. The rationale behind this is that the refractive properties of E 171 are only useful at relatively high amounts, requiring the addition of E 171. Challenges related to the measurement of Ti by ICP-OES in food are mainly related to sample preparation: TiO2 is practically insoluble and requires a mixture of concentrated hydrofluoric, sulfuric, and/or other acids for dissolution. However, the typically applied hydrofluoric acid solution is an ultrahazardous chemical that should be avoided for safety reasons. Hence, a digestion method using microwave digestion at 220°C in a mixture of nitric acid and sulphuric acid was optimized and evaluated for the analysis of total Ti in a variety of food samples collected before and after the ban of E 171. The measured concentrations of total Ti ranged from < 2 mg/kg to 13305 mg/kg, and from < 2 mg/kg to 26 mg/kg for foods known to contain E 171, and without added E 171, respectively. Cocoa products contained the highest natural Ti levels up to 25.5 mg/kg. When comparing four identical food items (brand, name, package) before and after the ban, the difference in total Ti concentration ranged up to 3 orders of magnitudes. Titanium concentrations above 50 mg/kg were only detected in food containing E 171. In the next phase, these analytical results will be compared with Ti concentrations measured by other analytical techniques (e.g. Raman, XRF). These results guide competent authorities in setting cut-off values when screening food products for the presence of the banned E 171 and give insights on the methods which are fit for purpose for such control.
- Keywords:
- Titanium dioxide, E 171, ICP-OES
- Download:
- IMEKO-TC23-2023-025.pdf
- DOI:
- 10.21014/tc23-2023.025
- Event details
- IMEKO TC:
- TC23
- Event name:
- 7th IMEKOFOODS Conference
- Title:
Worldwide food trade and consumption: quality and risk assessment
- Place:
- Maisons-Alfort/Paris, FRANCE
- Time:
- 25 October 2023 - 27 October 2023