The following information is fascinating but unconfirmed. I’ve read that eating hard cheese can actually help prevent cavities, so this article might explain the source of that bit of info.
If you know more or have additional links that will confirm or dispel this please leave a comment below.
The following is from “Lacto Fermentation: Raw Vegan Cheese Making And More”
B12 is created in the mouth and by bacteria in the intestinal tract. By destroying the mouth flora (through toothpastes or mouthwashes commonly available) one damages the B12 colonies in there. The mouth alone provides sufficient enough quantities of B12 for the very small requirements of vegetarians. A vegetarian need for B12 is, in fact, not as great as for individuals on a conventional diet. B12 is destroyed through heat, and people that consume meat often have the same B12 deficiency as Vegans do. B12 comes from the soil (this has been mentioned now by countless experts, a notable individual would be T. Colin Campbell in his book The China Study), earthworms (for example) are a common contributor to this vitamin complex in the soil. By over-washing the vegetables that grow close to the ground the B12 is washed off, hence eliminating ones natural source it. If you want to eat meat but also consume B12 I would assume you are better off eating live earthworms…
I make mention of B12 here because people will often ask if you can get B12 from fermented foods. The answer is yes, such as certain methods with coconut water, water from soaking wheat grains, and milk kefir grains/water kefir grains (milk kefir grains do not come from milk they derive their name as they are popularly used in making milk kefir), but if you eat raw vegetables from healthy soil that has not had its soil ecology depleted/destroyed through chemical based farming methods then you should stop worrying. Another great means of obtaining B12 is by sprouting your own micro greens in trays with quality organic soil. This is a cheaper solution than meat or organic vegetables.
Here’s a full article link cited above “Rethinking & Clarifying the Vitamin B12 Issue” By Dr Vivian V. Vetrano