Behavior of Brevibacterium linens and Debaryomyces hansenii as Ripening Flora in Controlled Production of Smear Soft Cheese from Reconstituted Milk: Growth and Substrate Consumption

Abstract

Experimental cheeses inoculated with Debaryomyces hansenii and Brevibacterium linens were ripened for 76 d under aseptic conditions. Triplicate cheese-making trials were similar as a result of efficient control of the atmosphere. In all trials, D. hansenii grew rapidly during the first 2 d and then slowed, but growth remained exponential until d 10 (generation time around 70 h). Total cell counts were higher than the number of viable cells, and after 10 d they remained around 3 x 10(9) yeast/g of DM. This difference resulted from the nonviability of a fraction of D. hansenii. After d 15, the pH of the rind was close to 7, and B. linens grew exponentially until d 25 (generation time around 70 h). The growth rate subsequently decreased but remained exponential (generation time around 21 d). Cell counts of D. hansenii and B. linens were correlated with the environmental technical conditions. Total D. hansenii counts were also correlated with total B. linens counts. Viable B. linens counts were related to rind lactate, and total counts depended on rind pH, internal lactate, and D. hansenii viable counts. The internal pH of the cheese depended on lactate concentrations, whereas surface pH was related to internal lactose, temperature, and relative humidity. These results suggest a determining role of the diffusion of the carbon sources in the ripening of smear soft cheese.

Contribution of several cheese-ripening microbial associations to aroma compound production

“…This fast growth in the first 10-15 d of incubation in our cheese-based medium corresponds to the development pattern usually reported for K. lactis [24] and D. hansenii [25] in soft cheese. Conversely, B. linens growth occurred latergenerally after 5 d of culture -and reached a plateau after d 10 or more, depending on the yeast it was associated With [24,25]. Lactose and lactate also exhibited similar degradation patterns to those observed during cheese ripening [23][24][25].…”

“…Conversely, B. linens growth occurred latergenerally after 5 d of culture -and reached a plateau after d 10 or more, depending on the yeast it was associated With [24,25]. Lactose and lactate also exhibited similar degradation patterns to those observed during cheese ripening [23][24][25]. The starter used in this experiment -which is extensively used in soft cheese-making -is mostly composed of homofermenters, which explains the high quantity of lactate detected [12,13].…”

“…Surface cheese-ripening bacteria, especially Brevibacterium linens, are known for their ability to produce VSC through the synthesis of a common precursor from L-methionine, methanethiol (MTL) [18]. Since these bacteria are salt-tolerant but also acid-sensitive [7], they generally develop in the late stage of ripening, after yeasts have deacidified the curd [24]. In LAB, the catabolism of amino acids -in relation to aroma compound synthesis -was thoroughly investigated and was revealed to be highly strain-dependent [37].…”

Microbial Community Structure and Dynamics of Dark Fire-Cured Tobacco Fermentation

“…Noteworthy is the specificity of the association between D. hansenii and several lactic acid and coryneform bacteria, including those we isolated from fermenting tobacco. These microbial consortia are typical of certain fermenting substrates that are characterized by a low C/N ratio, such as ripening cheeses (2,4,10,31,36,43,61), fresh sausages (7,47), vegetables (35), and algae (57). An association between D. hansenii and P. pentosaceus, revealed for tobacco samples (Tables 4 and 5), has previously been described for sorghum fermentation (35), and the same yeast has been isolated from the surface microflora of many brick cheeses in association with several coryneform bacteria, including C. ammoniagenes (58).…”

Gene Expression and Biochemical Analysis of Cheese-Ripening Yeasts: Focus on Catabolism of l -Methionine, Lactate, and Lactose

“…However, the contributions of yeasts to cheese flavor development during ripening are generally underestimated, and their roles are generally not well established. They develop at the early stages of ripening (16,21,22), when they participate in the deacidification of the curd through lactate/lactose consumption (11), and they could also be involved in flavor compound biosynthesis. Yeasts like K. lactis, K. marxianus, Y. lipolytica, and D. hansenii are found in a wide range of cheeses (11,12,16,21,31) and are expected to play an important role in the ripening.…”