I noticed that no one has responded to this question. Not that I have an "answer," but perhaps some information. I have never used an antifoggant with film, but it can be done. The tradeoff is rapid speed loss, so you would have to do tests to determine your effective film speed.(posted 8234 days ago)Anti-fog #1 is benzotriazole, typically used in a 1% solution (sometimes dissolved in ethylene glycol), and, in my experience, most often used as an additive to paper developers.
Anti-fog #2 is 6-nitrobenzimidazole nitrate, usually used in a .5% solution, often in astrophotographic and reversal processing applications for film.
I'd go with the #2 and run some tests before shooting anything important with old film. Maybe someone else can tell you how much you should add per liter of developer working solution. I found a URL describing its use as a pre-bath for 8mm movie film: http://8mm.filmshooting.com/the_lab/g3steps.php.