US FDA Food Labeling Regulations (21 CFR Part 101) 101.15: Prominence of required statements: conspicuousness, type size and contrast, English language with foreign-language duplication rules, and no obscuring design (101.15)

A food is misbranded if any required word, statement or information is not prominently placed with such conspicuousness, relative to the other words, designs and devices, and in terms that an ordinary person would be likely to read and understand under the usual conditions of purchase and use. Failure causes include insufficient label space taken by non-required matter, insufficient background contrast, obscuring designs or vignettes, smallness or style of type, and insufficient letter spacing. All required statements must be in English (or Spanish in Puerto Rico), and if any representation appears in a foreign language, all required statements must also appear in that language.