The Salak got announced at the same time as the Beni Imo and the Opo Squash on 2 March 2017. It's been two months of three items per day for Fresh and Flavorful and I have checked it every day since then. The odds of it not showing up even once in that time are not impossible, but very slim.
It has never been released into the store yet. I too am waiting on it for my gourmand pet, and getting a little salty about it since it's the last item I need from F&F.
This has happened before with another item, that it was just really unlucky and didn't go out the first month or so. Don't give up hope!
Feels like this happens every time new F&F foods are released. One of them just refuses to restock XD