"Well, there's a lengthy process to remove all impurities, and then the suit has filters as well." She gestured to the filters over her mouth. "We're very careful." She chuckled wryly. "But even without the vagaries of the quarian immune system, my DNA's written backwards from yours. I can only eat dextro food. Luckily they have some here, for some reason, though there are only two of us on this ship."