As an experience software testing engineer, quality assurance should be ingrained in your brain and your interviewer is looking to get a sense of your personal feelings towards it in your work with this question. In your answer, be sure to highlight QA's importance in reducing errors, maintaining specifications, testing failure parameters and preventing defects from occurring. In the end, make sure that quality is your mantra in the eyes of your interviewer by giving an example or two of how you put QA in the forefront of your work.