CHEESE | Secondary Cultures

Secondary cheese cultures are used in the manufacture of bacterial surface-ripened (Limburger, Mnster, Tilsiter), mold-ripened (Camembert, Brie, Roquefort), or Swiss-type (Emmental, Gruyere) cheeses. The contribution of secondary cheese cultures to milk acidification is limited or nonexistent. The main role of secondary cheese cultures is to direct the cheese ripening in a particular flavor direction through their additional metabolic properties above that of the primary starter culture. These properties may include, for example, halotolerance, growth at low pH, lactate utilization, carbon dioxide formation, proteolytic/peptidolytic activities, lipolytic/esterolytic activities, or amino acid converting activities. Geotrichum candidum, Penicillium camemberti, Penicillium roqueforti, Brevibacterium linens, various yeasts, and Propionibacteria constitute the principal group of organisms considered as secondary cheese cultures. Within the various species of secondary cultures, considerable strain variation exists, and thus selection of the appropriate strain for any given cheese type is of critical importance. Traditionally, the development of the secondary microflora has relied on the indigenous populations of molds, yeasts, and bacteria present in the cheese ripening rooms, cheese manufacturing equipment, or cheese milk. However, the reliance on these sources for the successful development of the necessary flora may not be practical for large-scale production. Therefore, commercially produced secondary cultures are normally used in order to improve process stability and ensure the early establishment of the desired cheese flora.