Making sense of organic labeling can be difficult, and many consumers do not understand the significance of the USDA Organic label. Since October 21, 2002, the following guidelines were established by the United States Department of Agriculture's (USDA) National Organic Program (NOP) to assure consumers know the exact organic content of the food they buy.
Single-Ingredient Foods
On foods like fruits and vegetables, look for a small sticker version of the USDA Organic label or check the signage in your produce section for this seal.
The word "organic" and the seal may also appear on packages of meat, cartons of milk or eggs, cheese, and other single-ingredient foods.
Multi-Ingredient Foods
Foods such as beverages, snacks, and other processed foods use the following classification system to indicate their use of organic ingredients.
100% Organic — Foods bearing this label are made with 100% organic ingredients* and may display the USDA Organic seal. 
Organic — These products contain at least 95-99% organic ingredients (by weight). The remaining ingredients are not available organically but have been approved by the NOP. These products may display the USDA Organic seal.
Made With Organic Ingredients — Food packaging that reads "Made With Organic Ingredients" must contain 70-94% organic ingredients. These products will not bear the USDA Organic seal; instead, they may list up to three ingredients on the front of the packaging.
Other — Products with less than 70% organic ingredients may only list organic ingredients on the information panel of the packaging. These products will not bear the USDA Organic seal.
Keep in mind that even if a producer is certified organic, the use of the USDA Organic label is voluntary. At the same time, not everyone goes through the rigorous process of becoming certified, especially smaller farming operations. When shopping at a farmers' market, for example, don't hesitate to ask the vendors how your food was grown.
*Salt and water are not included.
Source: Organic.org
