YEASTS AND THEIR POSSIBLE BENEFICIAL AND NEGATIVE EFFECTS ON THE QUALITY OF DAIRY-PRODUCTS

This review deals with yeasts and their potential use as starter cultu res in dairy products as well as their role as spoilage organisms. The taxonomy of relevant yeasts is described, with emphasis on molecular techniques and simplified identification systems applicable to industr y. Quantitative assessment of undesirable yeast contamination is discu ssed with regard to present requirements for quality assurance in dair ies. Special attention is given to the role of yeasts in the complex m icrobial interactions prevailing in several dairy products and to cont rolling fermentation, maturation and important product characteristics . Antimicrobial activities of yeasts, including secretion of 'killer f actors' with broad antimicrobial spectra are linked with the reported probiotic starter cultures. The desired properties of yeasts to be use d as starter cultures in the diary industry are summarized and areas o f research are proposed to gain the insight required to obtain full ad vantage of the active use of yeast cultures in a wider range of produc ts. Copyright (C) 1996 Elsevier Science Limited