You just have to take into account the status of each food. For example, bread cannot be eaten, since, surely it will be hardened. In order not to throw it in the trash, you can give the birds, but only a little or could suffer diseases due to bread preparation. As for alcoholic beverages, some evaporate, so it is convenient to throw them, the same as milk or atoles. On the other hand, water should be discarded because being exposed for so many hours and near plants, smoke and particles in general, it could be contaminated. Salt can be reused without problem.
What is done with the offering fruit?
Nothing. Ideally, At the time of putting the offering, a somewhat immature fruit is chosen so that when being exposed to the weather and without eating, as well as close to the heat of the candles, mature alone or accelerates the natural process. Thus, when the altar is removed, you can eat it quietly. He only remembers washing it before and getting rid of the one that is withered, in case it occurs.
What happens if you don't take off the offering on time?
Nothing. There is a myth that says that souls stay longer; However, it is not so. The legend of the Day of the Dead dictates that they actually visit their family and return, in fact, those wandering Ánimas in our world are looking for light back to leave the earthly plane. Therefore, in the offering a candle is placed for the soul alone, which is for all the dead to those who do not dedicate an altar. So in terms of beliefs, dihuntos souls do not stay here.
On the other hand, the expiration of food is an indicator to withdraw the offering. So if you do not take it away after the days of celebration, it is likely that the dishes, drinks, fruits and flowers begin to rot. Thus there may be unwanted insects such as flies, cockroaches and, inclusive, bedbugs.