Reuters: Livestock producers and other food industry groups filed a suit on Tuesday seeking to overturn a U.S. decision to allow higher levels of ethanol in gasoline and saying it could push up food prices. The Grocery Manufacturers Association, the National Meat Association and other groups sued the Environmental Protection Agency (EPA), saying regulators overstepped their authority when they ruled last month that gasoline retailers could sell fuel containing up to 15 percent ethanol. That is an increase…