Preservation of foods by fermentation depends on the principle of oxidation of carbohydrates and related derivatives to generate end-products which are generally acids, alcohol and carbon dioxide.These end-products control the growth of food spoilage microorganisms and because the oxidation is only partial, the food retains sufficient energy potential to be of nutritional benefit to the consumer Using its most rigorous, chemical definition the term ‘fermentation’ is applied to describe a strictly anaerobic process; however, the general understand-ing of the term now encompasses both aerobic and anaerobic carbohydrate breakdown processes. Most fermented foods, including the major prod-ucts that are common in the western world, as wellas many of those from other sources that are less well characterised, are dependent on lactic acid bacteria to mediate the fermentation process. The end-products of carbohydrate catabolism by these bacteria contribute not only to preservation but also to the flavour, aroma and texture, thereby helping to determine unique product characteristics. Being able to control the specific microorganisms or the succes-sion of microorganisms that dominate the microflora of foods (which is the basis of development of starter cultures) is therefore very desirable. Fermentation may also increase the nutritional quality of food by In this review, the role of the fermentation process in mediating antibiosis in fermented foods will be examined. This will focus almost entirely on the lactic acid bacteria whose activity in fermented foods and whose biochemical and metabolic properties are well characterised. In addition, the range of differenttypes of fermented products that are produced in different parts of the world will be briefly surveyed.The reader is directed to the excellent overviews in the text edited by Wood (1998) as a source of more detailed information on this topic. Fermented bever ages are not within the scope of this review. increasing digestibility as in the fermentation of milk to cheese. In addition, the contribution of functional attributes to a food through fermentation is likely to be one of the major research themes of the next decade and beyond. This not only includes tradition al activities such as the delivery of probiotic bacteria in products such as fermented milks, but will most probably be extended to the generation of functional components like vitamins, antioxidants and other compounds in a variety of different fermented foods (Steinkraus, 1998). Toxicity of foods may also be reduced by fermentation as occurs in the production of gari. A range of fermented foods, their country of origin and the microorganisms which dominate the fermentation, is shown in Table 1.