Srila Prabhupada about prasadam.
01. All to be served should be invited to sit on the floor, and prasadam should be served by qualified devotees.
02. Those who are served should be very clean, peaceful, and satisfied. They should eat before serving, if necessary. They should try not to speak while serving.
03. Serve just the right amount so that nothing is wasted.
04. Seniors should be served first. Householders should serve the guests. Old people and children should be served first.
05. Place salt and lemon on each plate before those to be served are seated.
06. Always serve water first.
07. Prasadam should be served in the following order:
a) First bitter preparations like sukta and bitter melon
b) Then spinach and other astringent items
c) Fried preparations and dahl
d) Various spicy vegetables
e) Sour items
f) Sweet preparations
g) Rice and capatis are staple foods and should be on the plate
08. Go around serving seconds until everyone is satisfied. Don’t be stingy, don’t hold anything back because you want to take it later. Prasadam is meant for distribution.
09. Do not touch plates with the serving spoon. Touching the plate contaminates the spoon. If a spoon becomes contaminated, you should wash it.
10. Don’t let your fingers touch any of the preparations, even water. Salt should never be served by hand, use a spoon.
11. Never touch prasadam with your feet or step over it.
12. Serve the prasadam from serving buckets.
13. Don’t drag buckets along the floor or make clanging noises with pot handles or utensils. Serve quietly.
14. After everyone is finished honoring prasadam, clean the place immediately.
Some of these instructions are found in SP’s letter to Kirtiraja (November 27, 1971)