In Satya-yuga, the rsis performed gomedha (cow) and asvamedha (horse) sacrifices for the welfare of the whole universe. [This proved the efficacy of the recitation of the Vedic mantras uttered during the sacrifice.] A very old cow or a horse would be sacrificed by being cut into pieces and placed in the fire. Afterwards, the rsis would utter mantras and the same animal would come alive in a beautiful young body.
The wife of a rsi who was about to perform a gomedha sacrifice was once pregnant. She had a very strong desire to eat, and she had heard that if, during pregnancy, one has a desire to eat and does not fulfill it, the newly born child will always have saliva coming from its mouth. This will be troublesome, both for the mother and the child. She had a strong desire to eat meat, and thus she stealthily took one piece of meat from the body of the cow that was offered in sacrifice. She hid it and was planing to eat it very soon. At that time, the rsi was finishing the sacrifice and uttered all the mantras for the cow to come to life. However, when he then saw the new cow, he noticed that there was a small part missing from her left side. He was surprised because this had never happened to him before. He went into meditation and realized that his wife had taken away a piece of meat during the sacrifice. Due to the effect of the mantras uttered by the rsi, there was now life in this small piece of meat. The wife now also understood what happened, and she quickly threw the meat far away. Shortly afterwards, red lentils sprouted from the blood of this meat, garlic sprouted from the bones (both garlic and the bones of a cow are white), and onions and carrots sprouted from the flesh. Thus, these foods should never be eaten by any Vaisnava, because they are in the mode of ignorance. -NM