Attenuated starters: an efficient means to influence cheese ripening - a review

Attenuated starters are lactic acid bacteria unable to grow and to produce significant levels of lactic acid but still delivering active ripening enzymes during cheese ageing. The attenuation can be performed by several methods: heating, freezing-thawing, freeze- or spray-drying, lysozyme or solvents treatment. Attenuated starters can also be obtained by the selection of lactose-negative mutants. Whatever the method used, various attenuated lactococci and lactobacilli species have been prepared and added to the milk in parallel to the primary starter. They increased in most cases proteolysis and lipolysis, reducing ripening time and improving flavour (bitterness reduction) as exhaustively presented here. Despite these promising results in cheese, the industrial use of attenuated starter is not widespread. One main reason is likely the empirical character of the attenuation methods proposed or the cast of this cell addition. Further research is needed to increase knowledge about these efficient cheese additives. (C) 2000 Elsevier Science Ltd. All rights reserved.