Nestlé Purina PetCare Co. has put a twist on homemade pet food by allowing dog owners to formulate a recipe online for shipment to their door. The St. Louis-based manufacturer this week entered one of the smallest segments of the $28 billion U.S. pet food market: customized diets. The American Pet Products Association’s most recent survey found that just 3 percent of dog owners purchased specialty food, such as raw or frozen diets, in 2012. The new line, Just Right by Purina, is neither raw nor frozen. Instead, pet owners go to JustRightPetfood.com, answer questions about the animal’s age, breed, weight and other characteristics, choose whether to include soy and grain, and pick a protein source: chicken, lamb or salmon. What emerges through a proprietary algorithm is a customized kibble diet, complete with the dog’s photo and a recipe name printed on the bag. “Every dog is unique and that’s why we believe the best solutions are personalized,” said Brian Lester, the brand’s director of marketing. “By combining a dog owner’s firsthand knowledge of their pet with Purina’s expertise, we can work together to help keep dogs happy and healthy throughout their lives.” Just Right by Purina is not intended as a substitute for diets that manage a health condition, such as skin, digestive or urinary issues, a spokeswoman said. Another Purina line, Veterinary Diets, is made for such purposes. The new food carries a premium price. A 24-pound supply packaged in four 6-pound bags costs $62.99, with free shipping. A single 6-pound bag is $24.99. Pet owners unsure how to answer a question during the ordering process may consult Just Right by Purina experts through an online chat or by email or telephone. Nestlé Purina, one of the world’s largest pet food companies, with brands such as Beneful, Alpo and Cat Chow, isn’t the first manufacturer of customized diets. The Cincinnati company Petbrosia launched personalized food for cats and dogs more than a year ago through its website, Petbrosia.com. Petbrosia CEO and founder Keith Johnson welcomed the competition. “Overall, this is a positive announcement for the industry, and we are happy to see other companies also recognizing that each pet has unique nutritional needs and that it is important for their health to have a diet that reflects that,” Johnson said. “We believe that more and more pet parents will discover that nutrition can be designed for their pets with today’s technology.” Like Purina, Petbrosia has customers complete an online pet profile to formulate a recipe. Petbrosia diets cost more—$67.99 for 20 pounds of salmon-based dog kibble, for example—but Johnson said “the quality of our ingredients is unmatched.” “Our diets use all-natural meats, fruits and vegetables grown and raised in America, and we never use unnecessary fillers or artificial additives,” he said. Compared with Just Right by Purina, which sends reordering reminders by email, Petbrosia offers a subscription program designed to automatically ship more food before the pet owner runs out. Petbrosia also touts that its formulations, which start with chicken or salmon, change with the pet, so nutritional levels are adjusted as the animal ages. “We’ve studied how aging can influence feeding for different breeds of pets and apply our insights,” Johnson said.