Highly nutritious yeasts (Candida utilis, now often Cyberlindnera jadinii) grown on media such as ethanol and sulfite liquor wastes — a rich source of protein and vitamins, especially B vitamins. Torula yeast is used as an animal feed supplement and as a food additive, where its savoury, umami character enhances soups, sauces, and vegetarian products; it may be labelled as natural flavouring. Grown on industrial by-products, it exemplifies single-cell protein valorising waste streams. Food-grade production demands controlled fermentation, thorough drying, and testing for contaminants — upgrading a feed ingredient to human-food standards.