main components should be:
-first aid
-protection ( clothing, something to sleep in/under, etc.)
-fire ( to make water drinkable, cook food, signal, etc. )
-water ( actual water and stuff to produce it: filters, purificatiob tabs, etc )
-food.
( -tools to make shelter, fire wood, etc. )
( -signal equipment )

what you use to put in those componens are personal and diterment by location. The more skilled AND experians you are, they less you need. Lack of knowledge and experians can be complemented with gear. The most importent criteria a kit should cover, is it has to suit YOU ! you can copy somebody's kit, but if you don't know how to use it, it ain't worth ****. It should provide the capabilty too give you all YOU need to keep YOU alive for more than 72 hours. Think what you can do ( and have done: experians ) and look wheather the gear covers all the criteria in conjustion with your skills.

Food choice is also personal, you can buy MRE's or other special "survival" foods OR just rotate your food supply in your bag with you normall food stuff. The last one is cheapest and provide you food which you are used to. Look for the ammount of energy/calories it give's you and don't forget too make it a balansed diet.