I think the difference with fire extinguishers, IT and accounting (particularly accounting - they look after the all-important money!) is that these are fairly tangible and broadly understood, whereas no matter how hard some of us QA/technical folk try, in some businesses the senior commercial people can't/won't understand what it is that we do. Things like "allergens", "pesticides", "bacteria" (especially bacteria) etc are pretty much just scientific mumbo-jumbo to too many of them, until it hits very painfully in the form of a recall or similar. At which point you may well get the "well why haven't QA done anything to prevent this?" question...
If your top management are bright enough to either understand these types of risk, or to recognise that their own limitations in this area are too great and to delegate this to someone with enough autonomy over resource to properly do something about it, then you're one of the lucky ones and the rest of the QA world looks on in envy 
Lesley's suggestion about providing examples is something that I'm sure many of us have resorted to over the years, but with some people even this isn't particularly effective.
Same with certification - it's not uncommon to now see that loss of BRC/FSSC/IFS/SQF status can cause large customers instantly walk away; it's written into many of their contracts that they can do exactly this. But I've worked in place that still do the "BRC is an impediment to sales" rant when we advised not buying from a completely unknown and usually entirely uncertified supplier who is suspiciously significantly cheaper than everyone else.
One thing to bear in mind is that to some commercial people, the view of any given situation may genuinely be the exact opposite of QA's - the cheap and potentially very questionable supplier looks like a great opportunity for increasing margin, rather than a massive pile of red flags and risk....