Cheese Effect
From MHWiki
"Anytime a mouse is not attracted to a trap during a hunt there is a chance for the cheese to turn stale. Some components are built using harmful chemicals that increase the odds of spoiling bait. Traps with a positive cheese effect help reduce the likelihood of cheese turning stale."
The cheese effect of bases and weapons determines the rate at which cheese stales. The available levels are very negative, negative, positive, very positive or no effect at all.