Rosemary Emerges as Antioxidant The herb rosemary has antioxidant properties with pet food applications, according to both Roudybush Inc. of Woodland, Calif., and Kemin Nutrisurance Inc. of Des Moines, Iowa. Roudybush has begun using a combination of rosemary, d-tocopherol (similar to vitamin E), and citric acid as a preservative in several of its bird foods. The formula replaces ethoxyquin as a preservative in Roudybush's Low-fat Maintenance, Maintenance, Breeder and High-energy Breeder pellets. The formula is comparable to ethoxyquin in terms of safety and efficacy, according to Roudybush. It is also more marketable because ethoxyquin was the "target of a tremendous amount of adverse publicity due to a poorly designed study of its safety in rats performed many years ago," a Roudybush spokesman said. Subsequent studies in dogs, rats and mice proved the preservative was safe, but the public damage had been done, according to Roudybush. Both rosemary and d-tocopherol have antioxidant properties. D-tocopherol has a low (compared to vitamin E) level of biological activity, and therefore reduced risk of toxicity. Citric acid binds to certain minerals, preventing them from starting oxidation reactions, according to Roudybush. Meanwhile, Kemin, a developer of feed additives, has sought clearance from the Food and Drug Administration for use of rosemary extract as a natural antioxidant in pet foods, said Brian Bahnsen, manager of regulatory affairs. The company has submitted supporting data to the FDA. Specifically, Kemin seeks a "letter of non-objection" from the FDA. Currently rosemary is approved for use as a flavor or spice in animal feeds, according to Kemin. "Rosemary extract's effectiveness as an antioxidant in pet food ingredients makes rosemary an excellent fit with today's consumers' preference for natural diets for their pets," says Dr. Donald Mattsson, manager of research and development at Kemin Nutrisurance. The company reports its rosemary extract product is being produced in a food-grade and kosher certified facility.