When manufacturers add titanium dioxide to foods and other ingestible products, it’s typically referred to as E171, which relates to food-grade purity.

In addition to controlling the reaction conditions, it is also important to carefully monitor the precipitation process to ensure that the desired precipitation percentage is achieved. This can be done through various analytical techniques, such as X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy, which can provide valuable insights into the particle size distribution, crystallinity, and purity of the titanium dioxide product.

A few non-dietary studies have reported adverse effects in the gastrointestinal tract of laboratory animals given food-grade TiO₂. However, these same effects were not seen when the same or higher doses of food-grade TiO₂ were administered in the animals' diet. Dietary studies best reflect how humans are exposed to TiO₂ from food. Thus, the Food Directorate placed the most emphasis on the results of these studies in the state of the science report.