THE BRONX - A nutrition advocacy group claims two major fast food chains in the Bronx and the rest of the city are still serving up significant amounts of trans fats.The Center for Science in the Public Interest says it decided to test the trans fats content in French fries at McDonald's, Burger King and Wendy's. Food served in restaurants across the city is supposed to have less than a half-gram of trans fats per serving.According to the study, an order of French fries from Burger King has 3.3 grams of trans fats per serving and Wendy's has 3.7 grams of trans fats per serving. McDonald's passed the test, with .2 grams of trans fats per serving.The organization said that the chains may not be breaking the law if the trans fats are coming from the food supplier and not from the restaurant itself.