Apparently B12 is a VERY difficult one to get from other than animal sources. Also, even though it is available in eggs, it becomes unavailable once they are cooked.
Vegetable sources are available, but most of those are seaweed based and unreliable.
Cobalt is needed to produce the B12 precursors. So are certain bacteria, which this information was weak in discussing, at least in my reading of it.
In the next paragraph it discusses one synthetic source that is stable and cheap, but the byproduct of it is CYANIDE. Not sure I would want to purposely put that in my wife's body.Vitamin B12 consists of a class of chemically related compounds (vitamers), all of which have vitamin activity. It contains the biochemically rare element cobalt sitting in the center of planar tetra-pyrrole ring called as Corrin ring. Biosynthesis of the basic structure of the vitamin is accomplished only by bacteria (which usually produce hydroxocobalamin), but conversion between different forms of the vitamin can be accomplished in the human body
In the discussion below it discusses how certain FERMENTED foods may contain sources of natural B12 precursors.A common semi-synthetic form of the vitamin, cyanocobalamin, does not occur in nature, but is produced from bacterial hydroxocobalamin and then used in many pharmaceuticals and supplements, and as a food additive, because of its stability and lower production cost. In the body it is converted to the human physiological forms methylcobalamin and 5'-deoxyadenosylcobalamin, leaving behind the cyanide, albeit in minimal concentration. More recently, hydroxocobalamin, methylcobalamin, and adenosylcobalamin can be found in more expensive pharmacological products and food supplements. The extra utility of these is currently debated.
The following cite mentions KIMCHI as a potential source of B12.Sources
Ultimately, animals must obtain vitamin B12 directly or indirectly from bacteria, and these bacteria may inhabit a section of the gut which is distal to the section where B12 is absorbed. Thus, herbivorous animals must either obtain B12 from bacteria in their rumens, or (if fermenting plant material in the hindgut) by reingestion of cecotrope feces.
Vitamin B12 is found in most animal derived foods, including fish and shellfish, meat (especially liver), poultry, eggs, milk, and milk products. However, the binding capacity of egg yolks and egg whites is markedly diminished after heat treatment. An NIH Fact Sheet lists a variety of animal food sources of B12.
Besides certain fermented foods, there are currently only a few non-animal food sources of biologically active B12 suggested, and none of these have been subjected to human trials.
Certain makers of kombucha cultured tea list vitamin B12 as naturally present in their product. One brand purports to contain 20% of the daily value of B12 in a single bottle, making kombucha a potential "high" food source of B12. Because kombucha is produced by a symbiosis between yeast and bacteria, the possibility that kombucha contains B12 does not contradict current knowledge. But no scientific studies have yet been published confirming the fact, nor whether the B12 in kombucha is the biologically active B12.
A Japanese fermented black tea known as Batabata-cha has been found to contain biologically active B12. Unlike kombucha which is made by fermenting already prepared tea, Batabata-cha is fermented while still in the tea leaf state.
Chlorella, a fresh-water single cell green algae has been suggested as a vitamin B12 source but not proven by any live animal assay. Algae are thought to acquire B12 through a symbiotic relationship with heterotrophic bacteria, in which the bacteria supply B12 in exchange for fixed carbon. Spirulina and dried Asakusa-nori (Porphyra tenera) have been found to contain mostly pseudovitamin-B12 (see Terminology) instead of biologically active B12. While Asakusa-nori (Porphyra tenera) contains mostly pseudovitamin-B12 in the dry state, it has been reported to contain mostly biologically active B12 in the fresh state, but even its fresh state vitamin activity has not been verified by animal enzyme assay.
One group of researchers has reported that the purple laver seaweed known as Susabi-nori (Porphyra yezoensis). in its fresh state contains B12 activity in the rat model, which implies that source would be active in humans. These results have not been confirmed.
Foods fortified with B12 are also sources of the vitamin although they cannot be regarded as true food sources of B12 since the vitamin is added in supplement form, from commercial bacterial production sources, such as cyanocobalamin. Examples of B12-fortified foods include fortified breakfast cereals, fortified soy products, fortified energy bars, and fortified nutritional yeast. The UK Vegan Society, the Vegetarian Resource Group, and the Physicians Committee for Responsible Medicine, among others, recommend that every vegan who is not consuming B12 foods fortify with supplements. Not all of these may contain labeled amounts of vitamin activity. Supplemental B12 added to beverages in one study was found to degrade to contain varying levels of pseudovitamin-B12. One report has found B12 analogues present in varying amounts in some multivitamins.
Unconventional natural sources of B12 also exist, but their utility as food sources of B12 are doubtful. For example, plants pulled from the ground and not washed scrupulously may contain remnants of B12 from the bacteria present in the surrounding soil. B12 is also found in lakes if the water has not been sanitized. Certain insects such as termites contain B12 produced by their gut bacteria, in a way analogous to ruminant animals. The human intestinal tract itself may contain B12 producing bacteria in the small intestine, but it is unclear whether sufficient amounts of the vitamin could be produced to meet nutritional needs.
68 Kwak, C. S.; Lee, M. S.; Lee, H. J.; Whang, J. Y.; Park, S. C. (2010). "Dietary source of vitamin B12intake and vitamin B12status in female elderly Koreans aged 85 and older living in rural area". Nutrition Research and Practice 4 (3): 229–234. doi:10.4162/nrp.2010.4.3.229. PMC 2895704. PMID 20607069. edit
This cite is a follow up of #68 above. In part it states:
69 Kwak, C. S.; Lee, M. S.; Oh, S. I.; Park, S. C. (2010). "Discovery of Novel Sources of Vitamin B12 in Traditional Korean Foods from Nutritional Surveys of Centenarians". Current Gerontology and Geriatrics Research 2010: 1. doi:10.1155/2010/374897. PMC 3062981. PMID 21436999. editfermented foods, such as Doenjang and Chunggukjang, and seaweeds contain considerable amounts of vitamin B12. Taken together, it can be summarized that the traditional foods, especially of fermentation, might be evaluated for compensation of the nutritional imbalance in the vegetable-oriented dietary pattern by supplying vitamin B12, resulting in maintenance of health status.