Though there is a test to be certified as an expert in cheese, those who pass it receive no formal title. Rather, those who are certified as cheese experts can pursue various jobs in the cheese industry.
People who sell cheese are sometimes referred to as cheesemongers. Many cheesemongers are experts in cheese, though the term cheesemonger does not specifically refer to a cheese expert. Affineurs are those who age cheese. The two titles are not mutually exclusive. Some affineurs may also be cheesemongers and vice versa, but that is not always the case. Someone who knows a lot about cheese, though, is simply a cheese expert. It is possible for a cheese expert to be neither a cheesemonger nor an affineur.