I have started paying more attention to the foods I eat, but I would like to know what to look out for when it comes to buying 100% organic foods.

What separates completely organic foods from partially organic foods?

Generally it's all down to certification.

As a shopper I want to know how to tell if someone has added chemicals to the production of food. Where on the package does it say? Or if packaged food in general is not considered organic? Things such as that.

For most items try to go to a farmers market. You can talk to the farmer and get the info you need about their products. Most of them are honest as they know word of mouth if they lie would hurt them. Grocery stores products are labeled if they are organic and must adhere to government standards to put that label on their products, in Canada at least.

If it says FDA certified organic I do not trust it. You want to stay away from a lot of the big name brands such as Kraft. The less ingredients listed the better. If there are a lot of ingredients you can't read in the other ingredient list stay away from it. . I buy Amish and Newmans as well as some other brands. Organic juices would be Lakeside, R. W. Knudsen, Looza,
With produce you want to buy with the PLU code starting with 9. PLU codes starting with 4 would be farm (sprayed) any other number you are buying inferior quality or gmo which has Round Up IN the seed.
Also stay away from anything diet or artificial sweeteners like Splenda, suraclose, nutrasweet, etc.

Here are some sites that list organic vs things to avoid

Organic Products (http://www.simpletruth.com/products/)

Who Owns Organic? The Organic Corporate Brand List v1.4 | Nutrition Wonderland (http://nutritionwonderland.com/2009/02/organic-corporate-hierarchy/)

Welcome | Seeds of Deception (http://seedsofdeception.com/)

Factory Farming Facts & the Food Industry - Important Policy News | Food, Inc (http://www.takepart.com/foodinc)

Food, Inc - YouTube (http://www.youtube.com/watch?v=QqQVll-MP3I)

Genetic Roulette Movie Trailer - YouTube (http://www.youtube.com/watch?v=Vv96D_ZURzs)

Thank you!