Characteristics of micrococci from the surface of Roquefort cheese

Abstract

Five different Micrococcus spp. were isolated from the surface of Roquefort cheese: M. roseus, M. sedentarius, M. lylae, M. luteus and M. varians. During culture on synthetic medium these bacteria produced acetic acid as the main volatile fatty acid and propanol as the main alcohol. On a complex medium these isolates synthesized additional volatile fatty acids. Studies were made of the effect of pH, of water activity adjusted with sodium chloride or sorbitol, and of temperature on growth rates. All five isolates were inhibited at a pH lower than 5.5 and grew at temperatures from 4° to 44°C; they were halotolerant and multiplied at NaCl concentrations up to 20%, corresponding to a water activity of 0.884.

Modeling the Influence of pH, Temperature and Culture Medium Composition on the Kinetics of Growth and Cysteine Proteinase Production by Micrococcus sp. INIA 528 in Batch Culture

“…Values of this parameter ranged from 0.599 at pH 7.5 to 0.648 at pH 8.0 (Table 1). Similar results were obtained by Vivier et al (1994) for several Micrococcus species. Biomass growth rate, which was scarcely affected by the pH of the medium, ranged from 0.3 h -1 for M. lylae VB 16 to 0.55 h -1 for M. sedentarius VB 15, respectively.…”

“…The minimal growth temperature (T min ) for Micrococcus sp. INIA 528 was 9 ºC (Table 3), slightly higher than the range -3 ºC/+7 ºC reported for five Micrococcus species (Vivier et al, 1994). Maximum growth temperature (T max ) for Micrococcus sp.…”

“…Maximum growth temperature (T max ) for Micrococcus sp. INIA 528 was 47 ºC (Table 3), whereas growth was arrested at 44 ºC for M. sedentarius VB 15, M. lylae (Vivier et al, 1994). The equation proposed by Ratkowsky et al (1983) was capable of fitting specific growth data (Figure 3).…”

“…The specific growth rate of Micrococcus sp. INIA 528 increased from 0.466 h -1 at 28 ºC to 0.685 h -1 at 37 ºC, whereas production of biomass had its optimum at 31 ºC ( (Vivier et al, 1994).…”