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Operational routine for constructing defined starters

For producing high quality smear cheeses, it is essential that bacteria show good smear and colour development, lead to good cheeses with sensoric properties and inhibit mould growth. The yeast should have good deacidification activity. An iterative routine for developing improved starters has been build. This routine shows the essential steps for delivering (1) a better-controlled process for the preparation of red-smear cheeses and (2) an approach useful for development of both new starters and new products. The steps in the process comprise: a. Create a target cheese sensory and analytical profile. b. Isolate microorganisms from target cheese and supply if necessary with strains with additional interesting properties. c. Test technological and microbiological properties of these strains. These properties of the strains are: Enzyme activities relevant for (volatile) flavour compounds, proteolytic activities, mould and undesired bacteria inhibititing activities, actual flavour formation by strains, growth properties. d. Choice of starter composition: dependent on product and technological requirements. The smear should consist of strains with flavour formation activities, proteolytic activities, colour forming activities and mould inhibition activities. The manifestation of these properties is determined by the cheese (production) environment. The best way to investigate the ability to develop a desired smear is to test in model cheese experiments and/or in pilot scale experiments. Start with the yeast; good deacidification of the cheese surface is a must for further development of the other microorganisms. Then bacteria of genera Staphylococcus, Arthrobacter, Brevibacterium and Corynebacterium preferably should be used. e. Actual testing on cheeses (model and experimental/pilot scale). It is important to stay close to production conditions for surface ripening. f. Analysis of experimental cheeses and compare with target cheeses profile (sensory and analytical, as determined under a.). g. If experimental cheeses are not acceptable, then change the microbial composition with strains with more or less of the desired activity, then repeat steps d, e, and f until the cheeses are acceptable. Using the approach explained above, a 5-species surface starter can be applied. In addition to their use in smear, starters should be used in the cheese brines. In spite of the large volumes of industrial brines, this application might still be practical because of the low concentrations needed.

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NIZO FOOD RESEARCH
Kernhemseweg 2
6718 ZB EDE
Netherlands
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