Siman 171

Our Sages, of blessed memory, forbade using types of food for a purpose that involves their disgrace, because it appears as if one is spurning the blessings of the Holy One, blessed be He. However, for other needs that do not involve disgrace to the foods—it is permitted to use them, even with bread which is the primary food, provided it is not something that makes it repulsive. But something that makes it repulsive is forbidden, because it is a disgrace to the bread and likewise to all types of food. Therefore, one may not place raw meat upon it because it makes it repulsive, and one may not pass a full cup over it lest it spill on the bread and make it repulsive, and likewise one should not support with it a bowl that is full of soup or porridge or something that makes it repulsive lest it fall on the bread and make it repulsive. But if it does not involve something that makes it repulsive, it is permitted to support with it, for this is not a disgrace, as a person may do all his needs with bread and certainly with other foods.

And so too, when one does so for human needs, even if he destroys it, since he does not do so in a way of contempt, it is permitted; for example, when one sprinkles the house with wine, and so too when one rubs the body with oil. And so we say in Shabbat (108a): A person may soak bread in wine and place it on the eye for medicinal purposes, even though the bread certainly becomes repulsive, nevertheless, since he does this in a way of healing and not in a way of destruction—it is permitted. And so they make a soak or a wash with wine, and they wash the hands with wine when there is no water, as is written in siman 160. But when there is water, it is forbidden to wash the hands with wine, whether raw or diluted, and even a washing that is not for the purpose of eating; but to remove filth it is permitted, whether with wine or with oil. And so it was taught in Berakhot (53b): Oil delays the blessing, and they supported it with a verse, see there. And Rashi explained: "Oil that they were accustomed to bring at the end of the meal to rub on the hands to remove their filth." Thus far his words. Therefore, they wash mayim acharonim with wine as is written in siman 181, because they remove the filth (see Taz and Magen Avraham). This is the wording of the Rambam in chapter 7: "One may not ruin foods in a way of contempt or kicking," see there, but anything that is not in a way of contempt but only for his needs—it is permitted.

One may not throw bread even if it does not become soiled, for the throwing itself is a way of contempt. Just as one may not throw bread, so too one may not throw other foods. However, in this there is a distinction: for the prohibition regarding other foods is only when they become soiled through throwing and become repulsive thereby, but anything that does not become soiled, such as walnuts, almonds, pomegranates, and quinces which have hard shells and the food does not become repulsive—it is permitted. It is not similar to bread, for "by bread man lives" and one must treat it with a measure of respect, but not other foods. And even though there is one who holds that there is no distinction, they did not concern themselves with this opinion (see Beit Yosef and Levush).

Regarding that which we say that it is forbidden to support a bowl of soup with bread lest it spill upon the bread and make it loathsome, this is when he is not eating from this bread at that time. However, to eat the bread with the soup—he is permitted to use the bread for the soup, meaning that he eats the porridge with the bread, and the bread serves in place of a spoon, as he takes the porridge with the bread and eats them together. And by the letter of the law, even if he does not eat them together but rather afterwards—it is also permitted, for this is not a way of disgrace but rather a way of eating. Nevertheless, those who are meticulous eat a bit of the bread every time they bring it into their mouth, and the remainder they eat afterwards. And he should not leave it, for it becomes loathsome to others, and it is proper to act thus, for if not so, he is using the bread as if it were mere wood, and it is not proper to do so (see Magen Avraham, subsection 3).

A person should not sit on a basket full of figs or dried figs if the basket is soft, because he crushes them with his body and they become repulsive, and all the more so regarding bread it is forbidden. However, he may sit on a cake of pressed figs or on a basket full of legumes, as they do not become repulsive through this. Whether it is permitted to sit on a chest containing books has been explained in Yoreh Deah siman 282, see there. And they may run wine through pipes before a groom and bride, as was the custom in ancient times, and there is no concern of contempt for liquids in this as they do this as a good sign, meaning that their tranquility should flow, and they do this for the sake of the joy of the groom and bride, and specifically that it does not go to waste, but rather that he receives it in a vessel at the end of the pipe's opening. And they may throw parched grain and nuts before them in the summer months, for they do not become repulsive, but not in the rainy months when they become repulsive. And even though they are in their shells, nevertheless from mire and mud they become completely repulsive. And it is forbidden to throw fine loaves ever, for bread is different from other foods regarding the matter of throwing, as I wrote in section 3. And those who throw wheat before grooms must be careful to throw only in a clean place, and also they should sweep them from there, so that they do not trample upon them with their feet. And one who sees food lying on the ground, he should not pass by and leave them but rather he should lift them, except when there is reason to fear sorcery (see Magen Avraham subsection 1). And it is stated in Taanit (20b) that one may not feed human food to an animal, see there (in Shabbat 50b it is stated that it is forbidden to crush olives even if his intention is to sweeten the fruit because they become repulsive through this, and the Rif explained that he wishes to wash his hands with it and it is possible to clean with soap, see there and in the Magen Avraham there).