The interviewer would like to know that you have an interest in keeping up their high standards of cleanliness. Give examples of times when you went over and above to meet cleanliness standards in your previous role(s).
"I am very concerned about cleanliness as it has everything to do with first impressions, and also the health of your customers. In my current position, I am always the first to notice anything out of place or in disorder. Rest assured, I would be proud to uphold the cleanliness standards at McAlisters Deli."
"I appreciate that McAlisters Deli has such a strong focus on cleanliness. I have taken some health and safety related courses and am confident that you will be more than satisfied with my standard when it comes to cleanliness."