Q. (On Asarah Beteveth on Friday this year) Can one preparing the food for Shabbat on Friday, taste it without swallowing, to see if it is well prepared? Do you then make a bracha?
A. Remoh (O.H. 567: 1) rules that on a communal fasting one should not taste the food without swallowing. Mishna Berura (ibid. 6) however permits when someone is preparing a mitzvah banquet, to taste a tiny bit, without swallowing any, to ascertain that it is salted and flavored properly. (See also Pri Megodim 250: 1 and Piskey Teshuvos ibid.)
Horav Shlomo Millers's Shlit'a opinion is that if it is necessary to taste the food l'kvod Shabbos as above, you don't make a brocho.
Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit"a