Application of wild starter cultures for flavour development in pilot plant cheese making

A number of wild lactococci of dairy and non-dairy origin which have the ability to produce unusual new flavours in model systems were studied with regard to various characteristics important for cheese making. All strains were found to be non-lysogenic and resistant to phages affecting strains present in commercial starters. Since the overall acidifying activity of many potentially interesting strains is rather low, they were used in combination with commercial starters. Defined-strain starter cultures (DSS) were prepared, composed of a combination of wild strains together with industrial strains, and tested in real cheese making (Gouda-type) experiments. The population dynamics of DSS were studied to understand the behaviour of the selected wild strains in the cheese environment. Wild strains showed various interactions with industrial strains in a defined-strain starter culture. Some wild strains, which were able to grow well together with industrial strains could be used relatively easily for practical applications. Other strains appeared to inhibit the growth of the industrial strains, due to the production of bacteriocins. In many cases the bacteriocin appeared to be nisin. Sensory evaluation revealed that the selected wild strains also produced typical flavours in a real cheese environment which corroborated the results obtained in model systems. GC/MS data confirmed the results of sensory evaluations