In an ideal world, you'd have an HR person who manages the process, but is not part of the decision-making function. In the good old days, applications remained sealed in their envelopes, in the same way that contract tenders work (or worked!) Email makes that difficult. So I can see why your Clerk has raised the issue. The shortlisting process will be managed by a group of people, so the fact that one of them may have seen the applications before the others is not a major issue.
I always use a formal evaluation and scoring system, both for shortlisting and interviewing, assessing applicants against the job description and person specification. These papers are kept as part of the official record.