Lithopone is manufactured by a process (Fig. 1) in which barium sulfide solution is prepared by reducing barite ore (BaSO ₄) with carbon and leaching the resulting mass.

In 2021, the European Food Safety Authority concluded that titanium dioxide is no longer safe in foods due to the same concerns over nanoparticles. As a result, titanium dioxide is now banned as a food additive in the EU. Although studies have shown that the absorption of ingested titanium dioxide is low, evidence suggests that titanium dioxide nanoparticles can accumulate in the body over time. Health Canada deemed it safe in 2022 but noted concerns. Unlike their European counterparts, Canadian officials did not consider studies performed with titanium dioxide nanoparticles alone. 

The gastrointestinal tract is a complex barrier/exchange system, and is the most important route by which macromolecules can enter the body. The main absorption takes place through villi and microvilli of the epithelium of the small and large intestines, which have an overall surface of about 200 m². Already in 1922, it was recognized by Kumagai, that particles can translocate from the lumen of the intestinal tract via aggregation of intestinal lymphatic tissue (Peyer’s patch, containing M-cells (phagocytic enterocytes)). Uptake can also occur via the normal intestinal enterocytes. Solid particles, once in the sub-mucosal tissue, are able to enter both the lymphatic and blood circulation.

This regulation entered into force on 7 February 2022. However, the Regulation included a six-month transitional period to allow food businesses time to phase out the use of this food additive and to reformulate their products using suitable alternatives. This period will end on 7 August 2022.