Review Article: A Review on the Microbiology of Indigenous Fermented Foods and Beverages of Ethiopia

Microorganisms have been playing a pivotal role in the fermentation of human foods and beverages since the beginning of human civilisation. Fermented foods and beverages are defined as products obtained through desirable biochemical changes caused by the action of microorganisms or enzymes. In indigenous fermented foods, the microorganisms responsible for the fermentation are usually the microflora naturally present on the raw substrate. Fermentation is one of the oldest and most economical methods of producing and preserving food and is found to destroy undesirable components, to enhance the nutritive value, flavour and taste of the food, and to make the product safe from pathogenic microorgansisms. Fermented foods are produced world-wide using various manufacturing techniques, raw materials and microorganisms. However, there are only four main fermentation processes: alcoholic, lactic acid, acetic acid and alkali fermentation. Alcohol fermentation results in the production of ethanol, and yeasts are the predominant organisms (e.g. wines and beers). Lactic acid fermentation (e.g. fermented milks and cereals) is mainly carried out by lactic acid bacteria. Acetobacter convert alcohol to acetic acid in aerobic conditions as in the production of vinegar. Alkali fermentation is basically a proteolytic type and often takes place during the fermentation of fish and