Titanium dioxide as used in sunscreens is commonly modified with other ingredients to ensure efficacy and stability. Examples of what are known as surface modifier ingredients used for titanium dioxide include stearic acid, isostearic acid, polyhydroxystearic acid, and dimethicone/methicone copolymer.

Food recalls:Some Jif peanut butter products recalled over salmonella outbreak concerns 

Though the regulated use of titanium dioxide in food products is legal in the U.S. and Canada, it's banned in some other countries, notably throughout Europe. In May 2021, the European Food Safety Authority announced that titanium dioxide can no longer be considered safe as a food additive.

In some studies, E171 was given to animals in drinking water without the stabilizers that keep E171 suspended in the liquid. Without stabilizers, E171 can settle and prevent the ingredient from combining with surrounding ingredients.