Take in only simple pure clean food---what is called Satvic food by the sages. That is to say, food which will not arouse the impulses and emotions, sharpen the passions, upset the equanimity, hamper health. Food offered to God is free from the evil vibrations that injure the individual in subtle ways. Food offered to the hungry and then eaten has also the same beneficial quality. Since food has a subtle impact on the feelings and thoughts of man, you have to be vigilant ever.

...Sathya Sai Baba, “The dead satellite” Divine Discourse 6 March 1970                        https://www.sssbpt.info/ssspeaks/volume10/sss10-07.pdf

When you go into the qualifications needed for seva, you will know that a pure heart---uncontaminated by conceit, greed, envy, hatred or competition is essential; also, faith in God, as the spring of vitality, virtue, and justice. Seva is the worship you offer to the God in the heart of everyone. Do not ask another which state you belong to, or which caste or creed you profess. See your favourite form of God in that other person; as a matter of fact, he is not 'other' at all. It is His image, as much as you are. You are not helping some 'one individual'; you are adoring Me, in him. I am before you in that form; so, what room is there for the ego in you to raise its hood? Duty is God. Work is worship. Even the tiniest work is a flower placed at the feet of God.

...Sathya Sai Baba “ A flower at His feet” Divine Discourse 4 March 1970                       https://www.sssbpt.info/ssspeaks/volume10/sss10-06.pdf