What concerns do you have about food? What are your ‘rules of thumb’ when food shopping?

The first thing I do when I go shopping is checking expire date and price. I am quite sensitive of spoiled food. I really hate my wife\'s habbits in which she put a lot of things in cold storage of refregerator. There are uncountable frozen food in there that might go bad. It is common to check the period of circulation and we misunderstand it as a expire date although we can eat it but I usually throw it away if it past the period of circulation because I want to prevent the portential health problem. Price of food is also major factor when I go shopping. There are numerous products from the different companies. Actually, I don\'t exactly know which is the famous products and safe ones. I usually choose the cheapest food and sometimes buy the things that I have heard from the advertisement. That is my rules of thumb. At the first, I check the period of circulation and then compare to the price.