I dont know about you but there are definitely times when I must use my pocket knives for food cutting and or food preparation. Mnay guys just use the standard gun oils and wd 40, but I just dont want to eat that stuff. I did several searches and found that some guys are ordering the food grade silicone for knife use like some restaurants use. If you check the prices on food grade silicone you will be taken back by the high price and wish there was a cheaper alternative, and in fact there is. About the silicone you dont want to be ingesting that stuff anyway so stay away from that for health reasons.
If you use your pocket knives for food simply clean them with spray cooking oil like pam. Any oil has rust preventative properties, and spray cooking oils effectiveness at preventing rust is quite high.
The Samurai used clove oil as a rust inhibitor on their weapons and swords. It was light, did not attract dirt and kept rust at bay. The downside today is that clove oil is difficult to find and expensive as the food grade silicone.
In addition to pam cooking spray you can get spray olive oil, spray canola oil and others.
I have tried them all and they all work great and dont add anything unwanted to your food.