Abstract
The biochemical changes occurring during cheese ripening are directly and indirectly dependent on the microbial associations of starter cultures. Freeze-dried Tibetan kefir coculture was used as a starter culture in the Camembert-type cheese production for the first time. Therefore, it's necessary to elucidate the stability, organization and identification of the dominant microbiota presented in the cheese. Bacteria and yeasts were subjected to culture-dependent on selective media and culture-independent polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE) analysis and sequencing of dominant bands to assess the microbial structure and dynamics through ripening. In further studies, kefir grains were observed using scanning electron microscopy (SEM) methods. A total of 147 bacteria and 129 yeasts were obtained from the cheese during ripening. Lactobacillus paracasei represents the most commonly identified lactic acid bacteria isolates, with 59 of a total of 147 isolates, followed by Lactococcus lactis (29 isolates). Meanwhile, Kazachstania servazzii (51 isolates) represented the mainly identified yeast isolate, followed by Saccharomyces cerevisiae (40 isolates). However, some lactic acid bacteria detected by sequence analysis of DGGE bands were not recovered by plating. The yeast S. cerevisiae and K. servazzii are described for the first time with kefir starter culture. SEM showed that the microbiota were dominated by a variety of lactobacilli (long and curved) cells growing in close association with a few yeasts in the inner portion of the grain and the short lactobacilli were observed along with yeast cells on the exterior portion. Results indicated that conventional culture method and PCR-DGGE should be combined to describe in maximal detail the microbiological composition in the cheese during ripening. The data could help in the selection of appropriate commercial starters for Camembert-type cheese.
Highlights
The main focus of research on cheese production in the past two decades has been on the improvement of quality characteristics and the production of healthier cheese [1]
An appropriate starter culture becomes increasingly important in cheese manufacturing and affects biochemical changes occurring during cheese ripening
The culturedependent approach indicated that Lactobacillus paracasei represents the largest and most commonly identified lactic acid bacteria isolates, with 49 of a total of 104 isolates, followed by Lactococcus lactis (31 isolates) and Lactobacillus kefiri (19 isolates)
Summary
The main focus of research on cheese production in the past two decades has been on the improvement of quality characteristics and the production of healthier cheese [1]. An appropriate starter culture becomes increasingly important in cheese manufacturing and affects biochemical changes occurring during cheese ripening. An upsurge of interest in developing suitable starter cultures in cheese production has occurred. Many researchers have proposed a variety of cultures suitable for use as starters, including bifidobacteria, lactococcus, lactobacillus, leuconostoc and enterococcus species [4,5,6,7,8,9]. The kefir culture has gained researchers’ attention with regarding to cheese manufacturing due to its potential effect on quality, health, and safety properties of the product. Lactic acid bacteria that exist in kefir grains have attracted a lot of attention because of their ability to inhibit the development of spoilage and the growth of pathogenic microorganisms, either by the production of lactic acid or by the expression of antimicrobial agents [14,15]. Freeze-drying is a solution for long-term preservation of microorganisms and convenience for shipping [18]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
