Which hook to use for listening on member profile updates

Hi, just in the final stages of development now, we’re doing the search module. The search functionality is to search for instances of word or part-word in a) recipe title b) recipe ingredients c) author name

So my search index has the username and screen_name of the author of each recipe, but what happens when they change their screen name? Now all the recipes they have contributed need to be re-indexed.

Is there a hook I can use for this? The best I’ve found is mod.member_settings.php “member_update_preferences” - but that doesn’t seem to catch updates to the username/password method “update_userpass”. There doesn’t seem to be a hook there. Same in CP, if an administrator changes a member’s screen name or username, the recipes have to be re-indexed.

Are there hooks that I can use for this, or do I have to alter the core files or sniff segments while listening on another hook such as “post_system”?