Natural microflora of different types of foods

The sources of thousands of different microorganisms in foods could be either natural or external. The microorganisms in foods are divided into three groups as molds, yeast and bacteria. Natural microflora of foods influences the quality, availability and quantity of products. Molds are generally known as spoilage microorganisms in foods. Therefore, usage of them in food processing is limited (i.e. mold ripened cheese, soybean fermented foods). Conversely, yeasts and bacteria are widely used as important microorganisms in food industry. They have ability to ferment sugars to some industrially important compounds such as ethanol, lactic acid, acetic acid and carbon dioxide. In addition, they can contribute to the texture, flavor and safety of foods. The microorganisms intrinsically existing in food play a key role in processing of numerous foods especially plant based fermented foods, milk and meat based fermented products. The aim of the present chapter is to discuss the natural microflora belonging to different foods and also to explain their functions during food processing.