The word Halal means "proper and permitted." Halal food is permitted by Allah (God) for Muslim consumption and includes all fruits, vegetables and grains. This was all the definition required for followers of Islam before the growth of processed foods. 

The processing of foods makes many formerly "vegetarian" meals, breads, yogurts or cereals no longer considered halal Ingredients used in processed foods may contain hidden haram (Forbidden) components for example, these may be in colors, flavors or processing aids, as well as in sub-ingredients used. Many vegetarian-type items do not meet halal standards for example, cheese, marshmallows, candies, baked goods and yogurt may have enzyme and gelatin ingredients from animals which are not halal. 

Many non-Muslims incorrectly believe that halal certification means nothing more than having a Muslim bless the plant and declare that the products are now halal. Some producers mistakenly believe that by not adding pork or any animal extract or alcohol ingredients, they can "self-certify" and label the product as halal for export or domestic sale.