As thousands of Jewish families in the Midwest enjoyed fresh, chalav Yisrael milk over Passover, few knew that their dairy drink was due to the efforts of a humble CPA named Yitzchok Eliyahu (Irwin) Kosofsky, who passed away prior to the holiday at the age of 89. Kosofsky was born in 1931 in Chicago to traditional Jewish immigrants from Lithuania and Ukraine, the oldest of three children. His lifelong connection to Chabad began when his parents, Louis and Bertha, sent him to the talmud Torah (after-school Judaic education program) at Congregation Bnei Ruven, then one of five Chabad synagogues in the city, and just a few blocks from their home on the then-predominantly Jewish West Side of Chicago. In 1942, the sixth Chabad rebbe—Rabbi Yosef Yitzchak Schneersohn, of righteous memory—visited Chicago for the second time, having been there previously in 1929. For the rest of his life, Kosofsky would lovingly recall the moment the Rebbe spoke to him and his talmud Torah classmates. RELATED Looking for a more rigorous experience, he joined a Talmud class taught by Rabbi Sholom Posner, then the shammash of the synagogue and the Rebbe’s emissary to the city. In high school, he continued his afternoon Torah studies, first at a Chabad yeshivah directed by Rabbi Yosef Wineberg, and later at Hebrew Theological College-Beis HaMidrash LaTorah, known today as Skokie Yeshiva. In 1951, he married Reitza Kushner. After earning a degree in accounting at Roosevelt College, he worked for many years as a CPA, and as comptroller for a company that refined precious metals. They joined the small core of young families deeply committed to Judaism and the ideals of Chabad-Lubavitch. After his retirement, Kosofsky devoted a significant part of his day to Torah study.

Spreading Chabad Ideals in Chicago Through the leading Chabad chassidim in Chicago, notably Rabbi Shlomo Zalman and Chaya Sarah Hecht, and Rabbi Herschel and Chava Schusterman, the Kosofskys developed a connection with the Rebbe—Rabbi Menachem M. Schneerson, of righteous memory. In the summer of 1955, he met the Rebbe for the first time. During that meeting, the Rebbe encouraged him to study Tanya, the foundational work of Chabad Chassidism, something he did for decades with a series of study partners. In the 1960s and ’70s, encouraged by the Rebbe, and under the direction of Rabbi Tzvi Hirsch Meisels (the Veitziner Rav), Kosofsky arranged the oversight and production of chalav Yisrael milk for Chicago. This involved sending a mashgiach to a farm and dairy in Wisconsin and trucking the milk into Chicago. At that time, only a handful of families were careful to drink the special milk, which was supervised to ensure that it contained no unkosher ingredients. There were many challenges over the years, but he received encouragement from the Rebbe and did not give up. The effort has since become fully independent and financially viable. At Lubavitch World Headquarters at 770 Eastern Parkway with Rabbis Chaim B. Halberstam and Yonasan Hackner, who worked the phone lines on the New York end to bring the Rebbe's talks to communities all over the world, including the live hookup in the Kosofsky home.