Cheese is characterized by a rich and complex microbiota that plays a vital role during both production and ripening, contributing significantly to the safety, quality, and sensory characteristics of the final product. In this context, it is vital to explore the microbiota composition and understand its dynamics and evolution during cheese manufacturing and ripening. Application of high-throughput DNA sequencing technologies have facilitated the more accurate identification of the cheese microbiome, detailed study of its potential functionality, and its contribution to the development of specific organoleptic properties. These technologies include amplicon sequencing, whole-metagenome shotgun sequencing, metatranscriptomics, and, most recently, metabolomics. In recent years, however, the application of multiple meta-omics approaches along with data integration analysis, which was enabled by advanced computational and bioinformatics tools, paved the way to better comprehension of the cheese ripening process, revealing significant associations between the cheese microbiota and metabolites, as well as their impact on cheese flavor and quality.

This study presents, the development of a green method to produce rich in thymol natural zeolite (TO@NZ) nanostructures. This material was used to prepare sodium-alginate/glycerol/xTO@NZ (ALG/G/TO@NZ) nanocomposite active films for the packaging of soft cheese to extend its shelf-life. Differential scanning calorimetry (DSC), X-ray analysis (XRD), scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FTIR) instruments were used for the characterization of such nanostructures and films, to identify the thymol adsorbed amount, to investigate the thermal behaviour, and to confirm the dispersion of nanostructure powder into the polymer matrix. Water vapor transmission rate, oxygen permeation analyzer, tensile measurements, antioxidant measurements, and antimicrobial measurements were used to estimate the film’s water and oxygen barrier, mechanical properties, nanostructure’s nanoreinforcement activity, antioxidant and antimicrobial activity. The findings from the study revealed that ALG/G/TO@NZ nanocomposite film could be used as an active packaging film for foods with enhanced, mechanical properties, oxygen and water barrier, antioxidant and antimicrobial activity, and it is capable of extending food shelf-life.

Two fermentations in skim milk were used to evaluate the effectiveness of the bacteriocin Thermophilin-T produced “in situ” by Streptococcus thermophilus ACA-DC 0040 in inhibiting spore outgrowth of Clostridium sporogenes ACA-DC 3888 under conditions simulating Graviera cheese manufacture and ripening. In the experimental fermentation, S. thermophilus ACA-DC 0040 and Clostridium spores were used. In the control fermentation, a non-bacteriocin-producing S. thermophilus ACA-DC 004 strain and Clostridium spores were used. The temperature program used and the pH changes were similar to those observed in Graviera cheese production and ripening. Clostridium spore counts and organic acids were measured during both fermentations. In the experimental trial, bacteriocin production by S. thermophilus ACA-DC 0040 reduced Clostridium spores by 1.79 log units during the ripening phase. Conversely, the Clostridium spore count significantly increased in the control trial from the 15th day onward by about 2.9 log units and showed elevated levels of acetic, propionic, and butyric acids, along with decreased lactic acid, which is clearly linked to the “Late Blow Defect” profile. The results of our study on the inhibition of C. sporogenes spore outgrowth provide useful information for establishing an effective biological control system, in addition to other barriers used during Graviera cheese manufacturing.