Is it necessary to "heal" clay pots? I'm from Mexico, and every time either my grandmother or mother bought a new clay pot, they started "healed" the clay pot by boiling water with vinegar, rub garlic on the outside of the pot, and let it rest all night long. 

I recently bought a clay pot, and it released black particles into my food. I asked why, and my mother told me it was because I didn't "heal" the pot.

I thought it was ridiculous, so that made my wonder if it's truly necessary to "heal" a clay pot, and if this belief is endemic of Mexico or is it also well know in other parts of the world as well. 

Hope this question isn't off topic. And if it is, feel free to flag it.
TL;DR: You should.
I don't own clay pots myself, so take this with a grain of salt. I found some information on the Bram Cookware website called Clay Cooking 101. It has recommendations as well as an instructional video.
The process apparently is called seasoning, rather than healing. Here is a short summary from the page:

Seasoning Your Clay Pot
Give your new clay pot love and it will love you back! Cookware that
will be used over a direct heat source on the stovetop needs to be
seasoned before its first use. This strengthens the pot and prevents
it from cracking. It will also make the pot more durable so it can
provide you with many years of fantastic cooking.

Now for the black particles in the food, I'm not certain what that could be; so it's probably best to play it safe and not eat the food.