Burger Farming Question

Does burger farming still work for big offers from the Police Department? If so, do I have to have nothing but burgers to get these offers? Currently, I have 75 burgers (200 Total Inventory, mostly burger supplies) and I haven't received a single burger offer yet (getting all kinds of other offers though).

Someone please help and let me know if this is still a viable strategy or if I was wasting my time and should just sell them all on the open market...