The second typically appears only on fresh produce, such as a sliced ham, that becomes dangerous as it gets older, in contrast to products like milk, yoghurt, vegetables, etc., which typically simply decline in quality but are not dangerous even weeks or even months past the best before date.

(A manufacturer actually was sued when, after encountering production issues, they recovered by simply relabeling the expiration dates on existing product. But the manufacturer won that suit decisively.)