Significance of Alay or Ritual Food Offerings
The underlying significance is any offering is believed also to bring back sixfold by way of blessings the aspirations offered to the ancestor, say the symbols of food and material things like heaven money or kim.
Thus, an offering of 8 oranges symbolizes double prosperity as orange color is like gold or kim in Chinese. while 8 is faat or riches and doubling prosperity.
One has to be careful though in food offerings as well as monetary kim or heaven money, differentiating it from offerings to deities or saints in Chinese traditions as compared to those for the dead. For example, fish when offered should not be whole but in fillet, or pork or beef should be sliced or chopped not whole meat, in the belief that since the dead don’t have spoon and fork, food preparation should have no bones and easy to eat!
And the core of these rituals are food offerings for the dead. This is apart from the usual Ghost Month rituals and offerings observed during the seventh month of the Chinese calendar.
These rituals can be done regularly at the pleasure of the descendant concerned for the afterlife welfare of the subject dead ancestor(s).
Offering them food in the afterlife brings blessings to the one making it by virtue of the kindred help from beyond the grave, say a telepathic form of guidance from ancestral spirits. Especially in day to day decision making to make a life worth living and even surpass the achievements of say, of a rich ancestor.