Abstract
The food industry is constantly striving to develop new products to fulfil the ever changing demands of
consumers and the strict requirements of regulatory agencies. For foods based on microbial fermentation, this
pushes the boundaries of microbial performance and requires the constant development of new starter cultures
with novel properties. Since the use of ingredients in the food industry is tightly regulated and under close
scrutiny by consumers, the use of recombinant DNA technology to improve microbial performance is currently not
an option. As a result, the focus for improving strains for microbial fermentation is on classical strain improvement
methods. Here we review the use of these techniques to improve the functionality of lactic acid bacteria starter
cultures for application in industrial-scale food production. Methods will be described for improving the
bacteriophage resistance of specific strains, improving their texture forming ability, increasing their tolerance to
stress and modulating both the amount and identity of acids produced during fermentation. In addition,
approaches to eliminating undesirable properties will be described. Techniques include random mutagenesis,
directed evolution and dominant selection schemes.