THE MICROFLORA OF TILSIT CHEESE .1. VARIABILITY OF THE SMEAR FLORA

The microflora of 25 Tilsit cheeses from 2 cheese plants was analysed. Debaryomyces hansenii was found to be the predominant yeast in all st ages of ripening. 75-95% of the bacterial flora consisted of corynefor m bacteria. Several of the isolates were identified as Arthrobacter Br evibacterium linens was found at 0-15%. In all cheeses tested, 5-15% o f total cell counts were made up by staphylococci. They were determine d as being not Staphylococcus aureus or other pathogenic staphylococci since all isolates were negative with respect to thermonuclease, clum ping, coagulase, and hemagglutination. Most of the isolates were hemol ysis negative. By genetical analysis, several selected isolates were c lassified as Staphylococcus equorum, one isolate as S. sciuri. Contami nation of cheeses with Fusarium moulds indicated the influence of the smearing strategy on spreading of undesirable microorganisms. In plant A. old cheeses were smeared first, then young cheeses were smeared wi th the same smear liquid. Fusarium contamination could be detected in all stages of ripening. In plant B, young cheeses (0-3 weeks) were sme ared with a commercial surface starter cocktail. In all cheeses of thi s age, problems with Penicillium-contaminations were observed. Older c heeses (>3 weeks) were smeared according to the strategy applied in pl ant A. Consequently, Fusarium moulds were detected in cheeses 4-8 week s of age.