word usage - How to distinguish between "blasphemy" and "sacrilege" in a non-religious context?

To blaspheme is to fail to show respect to a religious notion. While you could engage in a symbolic act of blasphemy, the fault is usually a verbal one. A case in point would be author Salman Rushdie's Satanic Verses, which was not deemed sufficiently deferential to the Islamic prophet Mohammed. Similar to heresy.

To commit sacrilege is to desecrate the sacred or holy. This would more strongly be a physical act, rather than a verbal one. Say, the kicking over of tombstones in a cemetery, or spraypainting the side of a cathedral.

In a gastronomic milieu, I'd say the use of mild peppers in a chili would constitute sacrilege, as it would insult the final product and create an abomination that demeans and shames a dish that many approach with reverence. But: To say that Rick Bayless doesn't know how to make chili would be blasphemy.