Most of us are very use to food being as close as the neighborhood grocery store or fast food joint. The reality is that in any disaster food supplies will quickly dry up and become unacessiable or unavailable. In a long term disaster government agency's will quickly become overwhelmed and their supplies exhausted. So if your counting on the government to take care of you I'm sorry but your sorely mistaken. The US Army did a study in the 1980s where they determined that people would be willing to steal for food without eating for a day and most would be willing to kill to obtain food after going without for three days.
I have seen first hand how quickly this can happen. I deployed in response to hurricane Katrina the day it made landfall with my Army Unit. I saw thousands of people over the coming days who were starving and had no food to eat. I saw riots at food distrubution locations when they ran out of food, water, and ice.  Even when we were tasked with delivering food to areas gunfights erupted over the food we were delivering as groups would start shooting at each other and even us. So as you can see people change during a disaster and will do horrible and horrendous things when they go without basic things like food for a few days. It is your responsibilty to yourself and family to ensure you have adequete food supplies to get yourself through a disaster.
How much food do I need to store?

FEMA's recomendation is to have at least a two week food supply per person on hand in the event of a disaster. I believe that is a good starting point and should get you through most short term disasters. You will need to asess your particular situation to determine how much food you can store.

What kind of food should I store?

There are many companies who sell food storage kits that are packaged in water proof and pest proof containers. These can be kinda of pricy. Other options to consider are canned goods, canning your own food, and other non perishable options. You need to assess your particular situation to determine what is the best option for you. 

How should I store my food supply?

At the very least you will want to store your food supply in a cool and dry place free of pest and vermin. I personally recommend storing your food supply in water proof and pest proof plastic buckets. These buckets can be easily found at your local hardware store or online and over very modular when it comes to storing them.
It is hard for many of us living in a modern country to imagine that a food shortage would ever be possible or even conceivable. Must of us are used to food on demand and as close as your nearest grocery store.