The Unsung Heroine of Kosher Food: Dr. Judith Leff
Dr. Judith Leff never sought the spotlight, but her impact on the world of kosher food was profound. This unassuming woman, with a warm smile, a sheitel perched gently on her head, and a vast understanding of complex biochemistry, quietly revolutionized how we understand kashrus in a world increasingly reliant on cutting-edge technology.
Born in Vienna in 1935, Judith’s early life was marked both by intellectual curiosity and harrowing upheaval. Fleeing the Anschluss, her family found themselves swept up in the chaos of World War II, tragically losing her father to Auschwitz. After the war, they rebuilt their lives in Paris, where Judith’s academic prowess shone, leading her to pursue a doctorate in plant physiology at the Sorbonne.
But her commitment to her faith remained unwavering, even when faced with a tough choice: taking a crucial exam on Shabbos, the Jewish Sabbath, with no flexibility offered. Judith opted instead to continue her studies, demonstrating a steadfast commitment to her faith that would define her life’s work.
Fate brought her to Jerusalem, where she met Nathaniel (Nat) Leff, a Harvard graduate studying at Hebrew University. They married, embarking on a life filled with academic exploration and international adventure, eventually settling in the United States.
While Nat pursued a successful career in economics, Judith found her calling in the world of science. She honed her skills in research, eventually joining the Orthodox Union (OU) in 1985, becoming instrumental in navigating the complex landscape of kashrus in a rapidly changing world.
"When I began at the OU thirty-six years ago, kashrus was about shechitah, and about not mixing meat and milk," says Rabbi Yechezkel Auerbach of KCL kashrus certification. "There weren’t many kosher products available. Today we have not only more products, but products being manufactured with technologies that were not available back then."
Dr. Leff’s expertise was invaluable in understanding how these new technologies interacted with kosher laws. As a trailblazer in the field of kosher food chemistry, she helped to lay the foundation for the OU’s Ingredient Approval Registry and Universal Kosher Database, ensuring that every ingredient met the stringent requirements of Jewish dietary laws.
“She raised the level of technological understanding to new levels,” Rabbi Menachem Genack, the OU’s CEO of Kosher Division, recalls. "She made sure the science was wedded to the halachos of food production, did everything with precision and care.”
Dr. Leff’s work often involved visiting factories and plants, often as the only woman present. Yet, she earned the respect of industry leaders with her impeccable knowledge and quiet authority. "
"The plant managers had a tremendous high regard for her," Rabbi Genack remarks.
But for Dr. Leff, the greatest reward lay not in accolades, but in ensuring that kosher consumers could trust the complex web of ingredients and processes behind the food on their tables. She spoke at conferences, shared her knowledge with rabbis, and tirelessly worked to bridge the gap between science and tradition.
Dr. Leff’s humility masked a deeply profound impact. "She was extremely intelligent," recalls her grandson Mordechai Yehuda Leff, "but she never flaunted her credentials. She avoided the spotlight. She wanted the world to understand the implications of the changing food technology for kashrus, but was not interested in sharing her private life."
Dr. Judith Leff’s legacy is one of quiet dedication and unwavering commitment. She represents the very essence of tzniyus, demonstrating that true significance doesn’t require fanfare or recognition. Through her tireless work, she ensured that kosher consumers could enjoy the bounty of the modern world with unwavering certainty and trust – a truly remarkable achievement.
