What's really in there?

Pet food stores say the recalls, which have been linked to contaminated wheat gluten from China, have prompted many consumers to shift to more expensive natural, organic, and holistic pet foods that contain recognizable meats, fruits, and vegetables.

Connie Kastelnik of West Roxbury said she initially was relieved to learn that the Hill's Pet Nutrition Inc. food she buys for her dog Dillon was not on the recall list. When Hill's recalled a dry cat food, however, she and her husband decided to start investigating more natural alternatives.

"When something like this happens, it destroys your trust in the industry," Kastelnik said. "You don't know if tomorrow there will be something else."

Rebecca Remillard , a veterinarian-nutritionist at the Angell Animal Medical Center in Jamaica Plain, said the shift to natural and organic products is understandable but not necessary nutritionally.

She said there is no difference nutritionally between a $1.19 can of Wellness Turkey Formula cat food containing turkey, chicken, sweet potatoes, carrots, cranberries, and zucchini and a 45-cent can of Friskies Special Diet Turkey & Giblets Dinner containing just turkey, with meat and poultry "byproducts."

According to the labels on the two cans, both meet the nutritional levels established by AAFCO, the Association of American Feed Control Officers.

Remillard said the Wellness product, manufactured by Old Mother Hubbard of Chelmsford, is being marketed to the sensibilities of the pet owner and not the pet. "You're familiar with chicken. You don't know what's in chicken byproducts," she said.

A spokeswoman for Old Mother Hubbard declined to comment. Lisa DiPietro , the co-owner of The Pet Cabaret in Roslindale, which sells Wellness and other natural pet products, said the two cans of cat food may provide the same level of nutrients but the more natural product is better for the animal.

Cats, DiPietro said, get nutrients more efficiently from meat than they do from wheat gluten, which some pet food manufacturers use as a thickener and nonmeat protein source. DiPietro's co-owner, Lisa Schlossberg , said natural food is also more economical in the long run because it is more filling, meaning pets need to eat less of it.

Kastelnik, a customer of The Pet Cabaret, said she isn't sure whether she will ultimately switch brands, but she says the more natural products certainly sound better. She said her Hill's dog food had ingredients like powdered cellulose, peanut hulls, and chicken and soybean meal. The pet food she is currently feeding her dog, a Bouvier des Flandres, contains turkey, chicken, barley, potatoes, apples, carrots, alfalfa sprouts, and even cottage cheese.

The Food and Drug Administration has traced the tainted wheat gluten to shipments from a single Chinese exporter between Nov. 3, 2006, and Jan. 23. The wheat gluten was contaminated with melamine, a chemical typically found in plastics and pesticides.

The problem was first uncovered early last month during tests by private-label pet food manufacturer Menu Foods Ltd. of Canada. On March 16, Menu Foods recalled 60 million cans and pouches of wet pet food. Recalls have since been made public by Hill's, Del Monte Foods Co., and Nestle Purina Pet Care Co.

Procter & Gamble Co., which markets the IAMS and Eukanuba pet food brands, ran ads in 59 newspapers this week apologizing to customers because certain wet foods manufactured for the company by Menu Foods had been included in the recall. "We are heartsick," the company said in the ad.

A spokesman for Angell Animal Medical Center in Boston estimated the hospital has seen about seven cases of kidney problems that appear to be linked to the tainted food, although he cautioned that no definitive connection has been made.

Pet stores and supermarkets have pulled recalled products while others have posted signs saying their food is not subject to the recall.

"It has opened people's eyes," said Jen Buehler , the sales supervisor at Pet Shop Girls in the South End, which sells natural pet foods. "It has opened a whole conversation with customers about what's good for their pet."

Whole Foods Market Inc. and PETCO Animal Supplies Inc. both say they have seen customers gravitating toward natural pet foods, although officials at the two chains declined to quantify how much sales of natural pet foods have increased.

"What we're seeing is a shift," said Don Cowan , a spokesman for PETCO.

DiPietro at The Pet Cabaret says customers are scrutinizing labels more closely and concluding they want better food for their pets. "We've just seen a steady uptick in business and a steady uptick in concern," she said. "People have become increasingly alarmed."

Bruce Mohl can be reached at mohl@globe.com.