sentences:  The milk may be concentrated by ultrafiltration to remove a portion of the water before addition of yogurt cultures.Alternatively, after culturing, the yogurt may be centrifuged or membrane-filtered to remove whey, in a process analogous to the traditional straining step.Brands described as "strained" yogurt, including Activia Greek, Chobani, Dannon Light & Fit Greek, Dannon Oikos, FAGE, Stonyfield Organic Oikos, Trader Joe's, and Yoplait have undergone the second process.