Question: When offering food during Qingming season and such, many will say aloud – ‘May so-and-so to come and eat.’ Is this right?
Answer: There is no need to call anyone by name. Simply offering the food with the clear intention along this line in mind will do – ‘May this be for so-and-so, if still around’. If not reborn as a hungry ghost, not a wandering spirit, and not in the bardo state, the food will not be needed. (If the food can only be taken when called, there is actually a low chance that the calling is done loud enough, or heard by the being who has to be near enough.) More important than offering food is to offer guidance and merits to facilitate rebirth in Pure Land. These practices can be adapted accordingly for doing so: https://purelanders.com/2016/07/19/what-should-be-chanted-during-after-a-funeral & https://purelanders.com/2012/06/25/general-buddhist-pure-land-practices-during-qing-ming-ullambana
Question: What happens to the offered food if so-and-so are no longer around?
Answer: If there are other beings with affinity and good enough karma, they can partake of the food. (This actually includes insects and animals, among the possible other unseen beings above.) There is no need to call for anyone in particular, or to call everyone. You would not want family members who might not understand, to think you are inviting ‘random’ spirits to take the offering meant for the ones they care about. Unless they already understand, they might think it is not right.
Question: If so-and-so are already deceased for many years, is there need to offer food?
Answer: Festive offerings might seem only customary, but it is also due to uncertainty, and for remembrance. Whether already reborn in a good realm or not, if Maha-vegan food offerings (free from meat, animal products, five pungent roots and alcohol) are made with respect, compassion and gratitude, there will be some merits created, as these generated intentions and related actions are wholesome. The merits can be further dedicated to all beings, which include the deceased, to alleviate their suffering, if reborn in a lower realm, to have a swifter good rebirth.
Unless there are clear signs of having had a good rebirth, and/or no signs of having a lower rebirth, many are unsure if the deceased are already reborn, and where they are reborn in. Those in the bardo state (which can last for 49 days after death), wandering spirits and hungry ghosts, (the last being an actual realm), will need food. However, offering food once a year is clearly not enough for wandering spirits and hungry ghosts. Beyond dedicated offerings for 49 days after death (for the bardo state, unless there are clear signs of having reached Pure Land), a further solution is to offer food before every personal meal in everyday life, by chanting this –
I offer this to the Buddhas,
I offer this to the Dharma,
I offer this to the Sangha.
I offer this to all sentient beings.
Amituofo. (10 times)