At work we call things like this "institutional knowledge." It can vanish very quickly!
Topps actually does pretty well in a lot of cases, since they're somewhat of a publisher, but boy you should see how most consumer product companies do on this front. Badly.
In my expertise of food and candy and so forth, institutional knowledge is non-existent. I recently debunked the internet's widely spread assertion of when Skittles first came to market, and even the Mars website was wrong on this. For the record, dates varied on the history, but the earliest anyone (including Mars) had was 1974. It was 1971.
And look at the story around Flamin' Hot Cheetos origins. An employee has apparently been taking credit for their invention the last dozen years (they came out in 1990-91) and someone finally did an investigation into it and found his claims lacking and likely not terribly valid. And that's just from 1990 - that's how quick things drop off the map. It is, most days, still shocking to me.