A lot of that depends on what you're eating, where you're sourcing your food and how healthy you are (actually all that pertains to any kind of biological 'waste', cow or otherwise). In that kind of situation though, it's more about making a positive use out of your waste than the quality of the fertilizer, especially if services like sewer and waste disposal are not available. All the better since you don't need to foul gallons of water if you handle your personal waste via compost. And that's also why I recommended ppl find that book, because it addresses some of the short-comings of human waste as fertilizer.