Food prepared for and offered to Krishna with love and devotion becomes completely spiritualized. Such food is called Krishna prasadam, which means “the mercy of Lord Krishna.”

Lord Chaitanya said of prasadam, “Everyone has tasted these foods before.  However, now that they have been prepared for Krishna and offered to Him with devotion, these foods have acquired extraordinary tastes and uncommon fragrances.   Just taste them and see the difference in the experience!    Apart from the taste, even the fragrance pleases the mind and makes one forget any other fragrance. Therefore, it should be under¬stood that the spiritual nectar of Krishna’s lips must have touched these ordinary foods and imparted to them all their transcendental qualities.”

Eating only food offered to Krishna is the perfection of veg¬etarianism. In the Bhagavad-gita Lord Krishna says that unless one eats only food that has been offered to Him in sacrifice, one will suffer the reactions of karma. He also states, “If one offers Me with love and devotion a leaf, a flower, a fruit, or water, I will accept it.” From this verse it is understood that we can offer Krishna foods prepared from milk products, veg¬etables, fruits, nuts, and grains. Meat, fish and eggs are not offerable. And a few vegetarian items are also forbidden— garlic and onions, for example, which are in the mode of dark¬ness. (Hing, or asafoetida, is a tasty substitute for them in cook¬ing.) Nor can you offer Krishna coffee or tea.

In preparing food, cleanliness is the most important principle. Nothing impure should be offered to God, so keep your kitchen very clean. Always wash your hands thoroughly be¬fore entering the kitchen. While preparing food, do not taste it, for you are cooking the meal not for yourself but for the plea¬sure of Krishna. Arrange positions of the food on dinnerware kept especially for this purpose; no one but the Lord should eat from these dishes. The easiest way to offer food is simply to pray, “My dear Lord Krishna, please accept this food,” and to chant each of the following prayers three times while ring¬ing a bell.

1. Prayer to Srila Prabhupada:
nama om vishnu-padaya krishna-presthaya bhutale
srimate bhaktivedanta-svamin iti namine
namas te sarasvate deve gaura-vani-pracharine
nirvisesa-sunyavadi-pascatya-desa-tarine

2. Prayer to Lord Chaitanya:
namo maha-vadanyaya krsna-prema-pradaya te krsnaya krsna-caitanya-namne gaura-tvise namah

3. Prayer to Lord Krishna:
namo brahmanya-devaya go-brahmana-hitaya ca jagad-dhitaya krsnaya govindaya namo namah

“I offer my respectful obeisances unto Lord Krishna, who is the worshipable Deity for all brahmanas, the well-wisher of the cows and the brahmanas, and the benefactor of the whole world. I offer my repeated obeisances to the Personality of Godhead, known as Krishna and Govinda.”
Remember that the real purpose of preparing and offering food to the Lord is to show your devotion and gratitude to Him.  Krishna accepts your devotion, not the physical offering itself. God is complete in Himself—He doesn’t need anything— but out of His immense kindness He allows us to offer food to Him so that we can develop our love for Him.

After offering the food to the Lord, wait at least five min¬utes for Him to partake of the preparations. Then you should transfer the food from the special dinnerware and wash the dishes and utensils you used for the offering. Now you and any guests may eat the prasadam. While you eat, try to appre¬ciate the spiritual value of the food. Remember that because Krishna has accepted it, it is nondifferent from Him, and there¬fore by eating it you will become purified.

Everything you offer on your altar becomes prasadam, the mercy of the Lord. Flowers, incense, the water, the food— everything you offer for the Lord’s pleasure becomes spiritu¬alized. The Lord enters into the offerings, and thus the rem¬nants are nondifferent from Him. So you should not only deeply respect the things you’ve offered, but you should dis¬tribute them to others as well. Distribution of prasadam is an essential part of Deity worship.