Microbiological, physicochemical, and sensory changes throughout ripening of an experimental soft smear-ripened cheese in relation to salt concentrations

To evaluate the effect of NaCl content on microbiological, biochemical, physicochemical, and sensorial characteristics, Munster cheeses were prepared from pasteurized milk seeded with 3 yeasts ( Kluyveromyces marxianus , Debaryomyces hansenii , and Geotrichum candidum ) and 5 ripening bacteria ( Arthrobacter arilaitensis , Brevibacterium aurantiacum , Corynebacterium casei , Hafnia alvei , and Staphylococcus equorum ). Experiments were performed in triplicate under 1.0%, 1.7%, and 2.4% NaCl levels in cheese. Ripening (d 2-27) was carried out at 12 degrees C and 96% relative humidity. These kinetics were both reproducible and repeatable at a 99% confidence level. For each microbial, biochemical, and physicochemical parameter, 2 kinetic descriptors (the maximal or minimal rate and its occurrence time) were defined. On d 2, the physicochemical variables (water activity, dry matter, and water content) were strongly dependent on the salting level. From d 2 to d 27, K. lactis was insensitive to salt, whereas D. hansenii was stimulated. Geotrichum candidum growth appeared very sensitive to salt in cheese: at 1.0% NaCl, G. candidum exhibited overgrowth, negatively affecting rind appearance, underrind consistency and thickness, and off-flavor flaws. A salt concentration of 2.4% induced death of G. candidum . A total of 4 bacteria ( A. arilaitensis , B. aurantiacum , C. casei , and H. alvei ) were moderately sensitive to salt, but S. equorum was insensitive to it. Salt level in cheese had a significant effect on carbon substrate consumption rates. The lactate consumption rate in 1.0% salted cheeses was approximately twice higher than under 2.4% NaCl. Data analysis of microorganism, biochemical, and physicochemical kinetics, as well as sensory analysis, showed that 1.7% NaCl was the best salt level in Munster-type cheeses to achieve an optimum balance between cheese characteristics, sensory qualities, and marketability.