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.
In three different dairies (A, B and C) located in Peloponess region (Southern Greece), traditional Feta cheese trials took place February to March using mixtures of sheep's and goat's milk. Only ...small variations in the evolution of microbial groups were observed during the whole ripening period. The main groups, such as thermophilic cocci, mesophilic lactococci, thermophilic lactobacilli, nonstarter lactic acid bacteria (NSLAB), presumptive
Leuconostoc, enterococci and micrococci, reached their highest levels during the first 16 days, and then declined approximately 1–2 log units until the end of ripening. The remaining groups investigated, comprising yeasts, coliforms and
Escherichia coli, were highest at day 4. The yeasts remained constant, while coliforms and
E. coli decreased sharply and were not detectable after 120 days of ripening. A number of 146 isolates (dairy A) taken from all stages of the manufacturing and ripening process were purified and studied.
Lactobacillus plantarum (58/146) and isolates of related species
Lactobacillus pentosus and
Lactobacillus paraplantarum (16/146) were the most common microorganisms found during cheese ripening.
Streptococcus thermophilus (23/146) and
Lactobacillus delbrueckii subsp.
bulgaricus (20/146) were detected in high levels up to 20 days, and then gradually reduced.
Enterococcus faecium (29/146) was found in all manufacturing and ripening stages.
•Manufacture of a spreadable, ovine fresh-cheese fortified with saffron extract.•Starter growth was not affected by saffron during cheese manufacture.•Enhanced antioxidant activity of spreadable ...cheese due to saffron supplementation.•Stability of saffron cheese color characteristics during cold storage.•Accepted sensory characteristics of the new product.
Saffron supplemented ovine fresh cheese was studied for its compositional, microbiological, color, antioxidant and sensory characteristics, during cold storage at 4○C for 30 days. The evolution of the total aerobic bacteria and the starter lactococci group, was not remarkably affected, during manufacture, however a significant decrease was observed during storage. In addition, the cheese exhibited a more intensive antimicrobial activity against coliform and enterococci groups, which could be attributed to the saffron presence. Saffron cheese didn’t show any remarkable changes in physicochemical properties. However, an enhanced antioxidant activity was observed on 1st day of manufacture and an increasing proteolysis rate was shown after 20 days of storage. Main changes were observed on color and sensory characteristics. The color coordinate b* was increased with the saffron concentration, suggesting that cheese color gets yellower. The cheese made from milk supplemented with saffron concentration of 50 mg/L was tastefully accepted and brought out traditional sensory characteristics, familiar to Greek consumers.
Myzithra whey cheese was made by the addition of ovine milk (10%) to whey, previously fermented by the bacteriocinogenic strain Streptococcus thermophilus ACA‐DC 0040, resulting in production of a ...bacteriocin (thermophilin T) titre at a concentration 40 960 ± 2560 AU/mL. The final antimicrobial activity in the ready‐to‐eat cheese was sufficient to inhibit the growth of coliforms and restrict the growth of bacteria of the Micrococcus group, thus contributing to and increased shelf life and the safety of cheese. A lower lactose content was observed in the cheese, which would lead to better acceptance by lactase‐deficient consumers. Moreover, the sensory characteristics of the cheese remained unchanged during the whole cold storage period, ensuring an extended shelf life.
Three fermentations in skim milk were used to study the effectiveness of the bacteriocin-producing
Streptococcus macedonicus ACA-DC 198 strain to inhibit
Clostridium tyrobutyricum LMG 1285T spore ...outgrowth under conditions prevailing during Kasseri cheese production and ripening. In fermentation A,
Clostridium spores were used solely; in fermentation B,
S. macedonicus ACA-DC 198 and
Clostridium spores were used; in fermentation C, a commercial starter culture and
Clostridium spores were used. The temperature program applied was similar to that of Kasseri cheese production and ripening. The presence of macedocin, the bacteriocin produced by
S. macedonicus ACA-DC 198, was confirmed in fermentation B. The results showed that macedocin was able to inhibit the outgrowth of
Clostridium spores, since significantly higher inhibition in spore outgrowth was detected in fermentation B than in fermentation C.
Lipolysis was studied during ripening of traditional Feta cheese produced in two small dairies, A and B. The cheeses were made from a thermized mixture of ewes’/goats’ milk by using yoghurt as ...starter and artisanal rennet from lambs’ and kids’ abomasa (cheese A) or mixed artisanal rennet with calf rennet (cheese B).
The acid degree value and the free fatty acids (FFA) contents in both cheeses increased sharply up to 18 d (pre-ripening period at 15 °C) and continued to increase throughout ripening. In both mature cheeses, acetic acid was found at high levels (13–18% of the total FFAs). However, except for this, all FFA contents differed significantly (
P
<
0.05) between the two cheeses throughout ripening. The levels of individual and total C2:0–C8:0, C10:0–C14:0 and C16:0–C18:2 fatty acids were significantly higher (
P
<
0.05) in cheese A than in cheese B. Presumably the difference, especially in the C2:0–C8:0 content, was due mainly to the type of the rennet used. Butyric acid was the dominant FFA in cheese A (20% of the total FFAs at 120 d), while the most abundant FFAs in cheese B were capric (18%) and lauric acid (18%). In general, the lipolysis degree of the two cheeses was higher than those reported for the industrially-made Feta cheese.
In organoleptic evaluation, cheese A had a piquant taste that was attributed to its high content of butyric acid and showed a significantly (
P
<
0.05) higher total score than cheese B.
Growth conditions that support bacteriocin (thermophilin T) production by Streptococcus thermophilus ACA-DC 0040 were identified. Synthesis of thermophilin T occurred during primary metabolic growth, ...while its specific rate of synthesis seemed to be optimal at T = 30°C. Thermophilin T activity rapidly decreased in the stationary phase, especially at high growth temperature (i.e. T = 42°C). In media with high content of complex nitrogen sources, high amounts of bacteriocin were detected in the growth environment, while about an 8-fold increase of thermophilin T titer and a 2-fold increase of specific synthesis rate was achieved when a fed-batch fermentation mode was applied.
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