Mohel on Shabbos
37. Spitting blood and wine into earth. Some mohelim spit the metzitza blood and wine into specially prepared earth (דרכ''מ יו''ד סי' רס''ה סקי''א ). Some are concerned for the issur of losh, as just adding the liquid is assur even without mixing it in (מג''א, מ''ב שכ''א סקנ''ז, ספר כורת הברית רסה סקנ''ז, ברכי יוסף יו''ד רסה סקט''ז ). Nevertheless, some allow it (כורת הברית שם ) because it is a פסיק רישא דלא ניחא ליה, and as far as the actual melacha, the mohel has no need for the blood to mix with the earth (הגר''נ קרליץ, חוט שני ח''א פי''ג סק''ב ).
38. Putting powder on the bandage. Some mohelim prepare a bandage for the mila by moistening it with a medicinal solution and then putting a powder designed to stop bleeding on it. During the week they spread the substances on the bandage with a finger or gauze, creating a sort of medical paste. Some point out that this is potentially losh on Shabbos (הגרי''א סילבר ).
Making Charoses on Shabbos
39. Erev Pesach this year [5785/2025] falls on Shabbos. To avoid issues of losh on Shabbos, the charoses for the Seder should be made on Erev Shabbos or Leil HaSeder. It should not be made on Shabbos since charoses is a thick mixture reminiscent of the mortar (רמ''א סי' תע''ג ס''ה ), so adding liquid to the crushed fruit is a concern of losh according to some opinions (see Issue 350, par. 34-35). According to the meikel opinion, it must be mixed with a shinui; according to the machmir opinion, it cannot be made on Shabbos, as the only thing mutar on Shabbos is a thin mixture with a shinui. Thus, it is always best not to make it on Shabbos (מג''א סי' תע''ג סקט''ז, מ''ב סי' שכ''א ס''ק ס''ח ).
Gum
40. Chewing gum on Shabbos is not an issur of losh even though one’s saliva mixes with a dry item, since chewing in the mouth is part of the eating process, not the melacha of losh. [As an aside, chewing the cud is only a sign of kashrus in animals, not humans...]
