When school starts in the next few days, children at Nightingale-Bamford, St. David’s School, and Birch Wathen Lenox will be eating greens from Satur Farms on the North Fork, drinking milk from Ronnybrook Farm Dairy in Ancramdale, N.Y., and eating eggs and apples from Breezy Hill Orchards in Staatsburg, N.Y.

Cater to You is going local with the school lunch menus at the six private school dining halls it manages. Contrary to expectations, the cost is about the same as with the previous suppliers.

“We’re in New York City and the farmers’ markets are buzzing, so why not take advantage of it?” Cater to You’s president, Anthony Trentacosti, said.

One client that helped bring on the change is the Little Red Schoolhouse and Elisabeth Irwin High School. Last semester, the fifth-graders petitioned for the school to stop buying products from major food conglomerates.

“I think the kids are right, from an ecological and philosophical point of view,” the school’s headmaster, Philip Kassen, said.

Cater to You has been responsive to a petition and to other requests from administrators and parents at the school that menus feature more vegetarian options, more whole grains, and fewer carbohydrates; that trans fats and high-fructose corn syrup be cut out, and for recess snacks to be all natural and organic. “The food is great: They provide tremendous variety, and it’s fresh and healthful,” Mr. Kassen said.

Another agent for change is Cater to You’s wellness program coordinator, Carolyn Wells, who has spearheaded the relationships with New York farms. “I feel morally that I should educate children as much as I can about how to eat healthfully,” Ms. Wells said.

To get his chefs at all six schools on board, Mr. Trentacosti gave a training session last week that included a lecture by the chef who introduced sustainable food to Yale University’s dining halls, John Turenne. As part of the training, the chefs closed their eyes before holding, smelling, and eating fresh-picked peaches.

At the meeting, Mr. Trentacosti also introduced a new company mandate: to eliminate prepackaged and nutritionally deficient foods. He provided chefs with a list of such items, including precooked bacon, prepared sauces, canned chocolate pudding, egg rolls, and preformed chicken tenders.

Cater to You still provides some children’s favorites, such as chicken tenders, which will be made from scratch and baked instead of fried.

Chefs will make their own tomato sauce and their own cheese sauce for macaroni and cheese.

Pizza will prepared with whole-wheat dough and fresh toppings.

Mr. Trentacosti is also working with his clients to help them improve their food-service infrastructure. At Fordham Preparatory in the Bronx, where service is à la carte, he is introducing a Web-based point-of-sale system that allows parents to set the amount the children have available for food, and also to view online exactly what their children are purchasing to eat.

At Birch Wathen Lenox, he is working with the school on an $80,000 project to create a tossed-salad station and hot bar in the dining room, which will help address the limited kitchen facilities.

He worked with St. David’s School on a $90,000 kitchen renovation that includes new china, steamers, sinks, storage shelving, and refrigerators.

Mr. Trentacosti said he hardly ever ate the cafeteria lunch when he was growing up at Catholic schools in Queens. “My mom packed a lunch for me almost every day,” he said.

His mother’s cooking led him to culinary training at New York City Technical College, followed by a few years working in restaurants in New York and California. In 1983 he accepted a job as chef-manager at St. Bernard’s, where the food was served family style and faculty members sat with students to teach them manners.

“When I started, the idea of school food was terrible,” Mr. Trentacosti said. “I set out to transform it.”

Using his restaurant experience and culinary school training, he made the breads, soups, and desserts from scratch, and he also tweaked the school’s traditional favorite, shepherd’s pie, using fresh mashed potatoes, lean meat, and nonfrozen vegetables. His recipe is still in use today.