⟩ Tell us whom you mentioned as reference in your resume, do mind If I contact your previous employer?
While preparing resume, always make note that mention only those reference who knows your previous work and credibility very well.
Don’t just name any person as reference because a person whom you listed as reference in your resume, should be responsible enough to handle any call received from your interviewed organization.
Or you can express your concern by telling them that you would like to keep your job search secret for some valid reason.