A McDonald's restaurant is pictured in Encinitas, California September 9, 2014. REUTERS/Mike Blake 
 
 (Reuters) - McDonald’s Corp (MCD.N) said it is testing new recipes for its staple Chicken McNuggets snack in some U.S. markets to cater to growing consumer demand for healthier food. 
 
 The company said on Wednesday it started testing a “simpler” recipe for the snack in 140 restaurants in Oregon and Washington state last month. 
 
 McDonald’s did not detail the specific ingredients in the new nuggets, but said it was a recipe “parents can feel good about.” 
 
 The nuggets being tested in Portland do not contain any artificial preservatives, the company said in an emailed statement. 
 
 McDonald’s also did not say whether it would roll out the new recipes nationally. 
 
 The news, which was first reported by Crain’s Chicago Business, follows McDonald’s announcement last year that it would phase out human antibiotics from its chicken supply in the United States within the next two years. 

 FILE - In this March 4, 2015 file photo, an order of McDonald's Chicken McNuggets is displayed for a photo in Olmsted Falls, Ohio. McDonald’s is testing Chicken McNuggets with no artificial preservatives... (Associated Press) 
 
 FILE - In this March 4, 2015 file photo, an order of McDonald's Chicken McNuggets is displayed for a photo in Olmsted Falls, Ohio. McDonald’s is testing Chicken McNuggets with no artificial preservatives... (Associated Press) 
 
 NEW YORK (AP) — Like the indestructible Twinkie, Chicken McNuggets are practically a culinary punchline, a symbol of hyper-processed fast food with a list of ingredients that reads like a chemistry exam. But now McDonald's wants to take at least some of the mystery substances out. 
 
 The world's biggest hamburger chain says it is testing a version without artificial preservatives. 
 
 It's the latest move by McDonald's to try to catch up with changing tastes and turn around its business, which has lost customers in recent years. 
 
 The new McNugget recipe is "simpler," and "parents can feel good" about it, the fast-food company said. 
 
 While McDonald's did not give full details about what is or isn't in the test recipe, it said the new McNuggets do not have sodium phosphates, widely used food additives that the company has said can keep chicken moist. Also, the McNuggets will not be fried in oil containing the artificial preservative TBHQ. 
 
 Chicken McNuggets have become an often-mocked symbol of heavily processed fast food since they were introduced in the 1980s. The breaded and fried nuggets are made of ground-up chicken rather than intact chunks of meat and are delivered to stores frozen. 
 
 The company said it began testing the new recipe in about 140 stores in Oregon and Washington in March. The test was first reported by Crain's Chicago Business. 
 
 As people pay closer attention to food labels, companies across the food and drink industry have adjusted recipes to remove ingredients that may sound unappetizing. 
 
 Last year, for instance, McDonald's changed its grilled chicken recipe to replace sodium phosphates with vegetable starch and to remove maltodextrin, which was used to increase browning. 
 
 The McNugget test reflects the sensitivities of parents of young children in particular. McDonald's has long targeted families, with its Happy Meals and Ronald McDonald mascot. 
 
 McDonald's said it is getting feedback from customers with the McNugget test, and did not say when it might launch the new recipe nationally. 
 
 Last week, McDonald's said sales rose 5.4 percent at established U.S. locations during the first three months of the year. The results were boosted at least in part by higher prices and the closing of underperforming stores. 
 
 McDonald's Corp., based in Oak Brook, Illinois, has more than 14,000 locations in the U.S.
– While the Big Mac is getting bigger, McDonald's Chicken McNuggets are getting "cleaner." Since early March, McDonald's has been testing a "simpler recipe" free of artificial preservatives (McNuggets are already free of artificial flavors and colors) at 140 restaurants in Oregon and southwest Washington state. The goal is to expand the new recipe across the country before the Summer Olympics kick off on Aug. 5, reports Crain's Chicago Business, though a rep wouldn't confirm that. "This is very much a test," the rep says, adding the response has been favorable so far. McDonald's hasn’t revealed the full list of ingredients, but lemon juice solids and rice starch are in, while sodium phosphates are out. Preservative TBHQ is also absent from the oil used for frying, per the AP. It's a recipe "parents can feel good about while keeping the same great taste they know and love," the company says. McDonald's also recently revised its Egg McMuffin recipe and replaced sodium phosphates in a grilled chicken recipe with vegetable starch. Last year, it announced it would eliminate human antibiotics in its US chicken supply within two years, per Reuters. (McDonald's announced earlier this month that it is doing away with a menu item.)