Actually I wouldn't go to a grocery store. Almost all you need to survive are in camping supply and outdoor stores. They have guns, ammunition, warm sleeping apparatus, clothing and all the freeze dried and unperishable food you can handle. Plus the grocery store will be a very dangerous place because of looters and thieves not to mention huge congregations of people are zombie magnets.
You guys, don't believe what you see in the media. If there was an event such as this it would be similar to rabies or some other kind of disease that attacks the brain bypassing the human circulatory system.