Surface-ripened cheese

Micrococci comprise approximately 78% of the nonlactic bacteria in raw milk Cheddar cheese (Alford and Frazier 1950). The proteolytic system of Micrococcus freudenreichii functions optimally at 30 °C and at a pH near neutrality (Baribo and Foster 1952). An analysis of pro-teinases present in 1-year-old Cheddar cheese indicates that micrococci may contribute to proteolytic activity (Marth 1963). Proteolytic micrococci also contribute to the ripening of surface-ripened cheeses such as brick and Camembert (Lenoir 1963 Langhus et al. 1945). Micrococcal proteases probably contribute to development of ripened cheese flavor when ripening temperatures are above 10°C (Moreno and Kosikowski 1973). This effect results from degradation of /3-casein. 

Furtado, M. M. and Chandan, R. C. (1985). Ripening changes in blue-mold surface ripened cheese from goat s milk. J. Food Sci. 50, 545-546. 

Lecanu, L., Ducrest, V., Jouquand, C., Gratadoux, J. J., and Feigenbaum, A. (2002). Optimization of headspace solid-phase microextraction (SPME) for the odor analysis of surface ripened cheese. ]. Agric. Food Chem. 50, 3810-3817. 

Karahadian, C., Lindsay, R.C. 1987. Integrated roles of lactate, ammonia, and calcium in texture development of mould surface-ripened cheese. J. Dairy Sci. 70, 909-918. 

Aside from the distinctively-flavored, washed, surface-ripened cheeses mentioned earlier ( 9, 1, 30), methanethiol has been recognized as a contributor also to the flavor of mature mold surface-ripened cheeses, including Camembert and Brie (31, 32,... 

In surface smear-ripened cheeses, e.g. Munster, Limburger, Tilsit, Trapist, the surface of the cheese is colonized first by yeasts which catabolize lactic acid, causing the pH to increase, and then by Brevibacterium linens, the characteristic micro-organism of the surface smear but which does not grow below pH 5.8, and various other micro-organisms, including Micrococcus, Arthrobacter and coryneform bacteria. 

Molimard, P., Spinnler, H.E. 1996. Review Compounds involved in the flavor of surface mould-ripened cheeses origins and properties. J. Dairy Sci. 79, 169-184. 

Mold-ripened cheeses are inoculated with mold spores which germinate and, via metabolic transformation, produce additional characteristic flavor compounds. Blue-vein cheeses are good examples. In these cheeses, surface molds, yeasts, and bacteria (micrococci) become dominant as the cheese pH drops due to the lactic flora early in maturation. The main... 

Volatile fungal metabolites contribute to the organoleptic properties of several other foodstuffs. Surface mould ripened cheeses such as Brie and Camembert are produced using Penicillium camembertii and, more commonly, P. caseicolum. Oct-l-en-3-ol accompanied by smaller amounts of octa-l,5-dien-3-ol and 3-one are major contributors to the aroma. These organisms also have the ability to produce 2-alkanones from fatty acids and these contribute to the odour of the cheese. 2-Methylisoborneol (7.70) and 2-methoxy-3-isopropylpyrazine (7.71) have been detected in mature cultures. An unpleasant earthy flavour encountered in some aged cultures has been attributed to the excessive produetion of 7.71. 

In ripened cheeses (Fignre 2.13), the fat migrates to the surface because of the breakdown of the protein shell that was covering the fat globule. This event results in the oily appearance of ripened cheeses. 

FIGURE 2.13 Cryo-SEM micrograph of ripened cheese. Eat globules on the surface. 

Nisin can be used for semolina and tapioca puddings and similar products (3 mg/kg), ripened and processed cheeses 12.5 mg/kg) and Mascarpone cheese (10 mg/kg). Natamycin may be used for surface treatment of hard, semi-hard and semi-soft cheeses and dried, cured sausages (1 mg/dm surface up to a depth of 5 mm). Lysozyme is used in quantum satis (a Latin term meaning the amount, which is needed), for example, to preserve ripened cheeses. 

Proteases of L. bulgaricus and L. helveticus contribute to the ripening of Swiss cheese (Langsrud and Reinbold 1973). Strains of thermo-duric lactobacilli are generally more proteolytic than S. thermophilus (Dyachenko et al. 1970). The proteinase activity of L. bulgaricus is optimal at pH 5.2-5.8 and is associated with the cell envelope (Argyle et al. 1976). Some strains of L. brevis (Dacre 1953) andL. lactis (Bottazzi 1962) are also proteolytic. Surface-bound aminopeptidase from L. lactis, characterized by Eggiman and Bachman (1980), is activated by cobalt and zinc ions and has optimum activity at pH 6.2-7.2. A surface-bound proteinase and carboxypeptidase are also present in L. lactis. 

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