Short of B12? From: http://www.vegsoc.org/info/b12.html

Human faeces can contain significant B12. A study has shown that a group of Iranian vegans obtained adequate B12 from unwashed vegetables which had been fertilised with human manure. Faecal contamination of vegetables and other plant foods can make a significant contribution to dietary needs, particularly in areas where hygiene standards may be low. This may be responsible for the lack of aneamia due to B12 deficiency in vegan communities in developing countries.

Ok but seriously, if you need some B12.  Good sources:

• Liver (more B12 by a mile but going to taste awful) > 40µg

If you want to stay veggie:

• Mushrooms
• Fortified B12 foods
• Vitamin Supplements

B12 content in food is measured in micrograms µg. Recommended daily intake is between 2 –3 µg per day.

Intrinsic Factor

So in order to absorb B12, your body produces this thing called Intrinsic Factor.  It sounds more like a metric than a biological entity but not having enough Intrinsic Factor means that you cant get B12 into your blood stream.  If this is the case, you may have to get your B12 via injections.

Analogous B12 and Blood Tests

Tofu, Tempeh, Spirulina all appear to have B12, but not quite.  They are known as analogous B12, enzymes that appear as B12 in a blood test but dont do the same job.  In fact, there presence can effect the uptake of B12

More

Dietary Supplement Fact Sheet: Vitamin B12

Vegetarian Network Victoria – Nutrition: Vitamin B12 and Vegan Diets