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Assyrtiko is a rare ancient grape variety of Greece, which is known to produce Protected Designation of Origin (PDO) Santorini white wines. Besides the famous character of the volcanic terroir, Assyrtiko of Santorini is also marked by a low pH value and sharp acidity. The aim of the present study was to apply a new inoculation procedure that modulates the fermentation process by maintaining the unique sensorial characteristics of Assyrtiko wines based on acidity. For this purpose, the Lachancea thermotolerans species, known for the formation of lactic acid, was tested in sequential fermentation with three different Saccharomyces cerevisiae strains. At the end of the fermentation process, implantation control for S. cerevisiae strains (interdelta sequence profile analysis) was performed, oenological parameters were determined according to the OIV protocols, and the volatile compounds produced were measured by gas chromatography–mass spectrometry (GC/MS). Finally, all produced wines were evaluated by quantitative descriptive analysis by two groups of experts; the Greek team of oenologists from Santorini Island specialized in Assyrtiko wines, and the French team of oenologists specialized in wine from Bordeaux. As expected, the inoculated strain was the one that dominated the fermentation process, but nine S. cerevisiae indigenous strains were also identified in the produced wines. Lachancea thermotolerans produced 1 g/L of lactic and also modulated the volatile profile of the wines independently of the S. cerevisiae strain used. The origin of the panelists played an important role in bringing up sensorial traits, such as acidity. Our results led to a new interesting application of L. thermotolerans for white wine production adapted to climate change claims. [ABSTRACT FROM AUTHOR]

Traditional Greek Graviera cheese is often produced from thermized milk to control undesirable bacterial contaminants. Since thermization also reduces the desirable lactic acid bacteria (LAB) microbiota of raw milk, natural undefined or commercially defined starters are used. This study evaluated effects of the type of starter added to bulk thermized milk on the microbiology of mature (day-90) Graviera cheese. Cheeses produced with a natural starter culture (NSC) in non-concentrated yogurt-like form or a commercial starter culture (CSC) containing Streptococcus thermophilus and various Lactococcus lactis strains in concentrated freeze-dried form, were analyzed microbiologically, and 200 LAB isolates (100 from each type of cheese) were identified. The LAB microbiota of the mature CSC-cheeses was dominated by nonstarter strains of Lactobacillus paracasei and Lb. plantarum whereas indigenous Enterococcus faecium and E. durans strains of high phenotypic and genotypic diversity predominated in the respective NSC-cheeses. Populations of enterococci in CSC-cheeses were subdominant by 10 to 100-fold compared with those in NSC-cheeses; E. faecium was the most frequently isolated Enterococcus species from the mature CSC-cheeses. Sporadic or no isolates of other LAB species, including the commercial S. thermophilus and Lc. lactis starter strains in the CSC-cheeses and the natural S. thermophilus and Lactobacillus delbrueckii subsp. bulgaricus starter strains plus indigenous Lactococcus, Leuconostoc and E. faecalis in the NSC-cheeses, were detected. In conclusion, the replacement of the NSC with the CSC controlled growth of dairy enterococci in favor of mesophilic nonstarter lactobacilli during ripening. While safety concerns associated with the inefficiency of NSCs to prevent outgrowth of indigenous enterococci suggest that CSCs should be preferred by traditional Greek Graviera cheese processors, panel sensory evaluations showed that the NSC-ripened cheeses were of slightly lower appearance but of occasionally higher flavor scores than the CSC-ripened cheeses., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Traditional Greek cheeses are often produced from thermized milk (TM) with the use of commercial starter cultures (CSCs), which may not inhibit growth of Listeria monocytogenes completely. Therefore, this study evaluated the behavior of an artificial L. monocytogenes contamination in commercially TM (63 °C; 30 s) inoculated with a CSC plus Lactococcus lactis subsp. lactis M104 and/or Enterococcus faecium KE82, two indigenous strains producing nisin A and enterocin A and B, respectively. Inoculation treatments included TM with the CSC only, and TM without the CSC but with strain M104 alone, or combined with strain KE82. All treatments were incubated at 37 °C for 6 h followed by 66 h at 18 °C. L. monocytogenes grew by 0.66-1.24 log cfu/ml at 37 °C, whereas its further growth at 18 °C was retarded, suppressed, or accompanied by different inactivation rates, depending on each TM treatment. Strain M104 caused the greatest inactivation, whereas the CSC per se was the least effective treatment. Strain KE82 assisted the CSC in controlling pathogen growth at 37 °C, whereas both reduced the nisin A-mediated antilisterial activity of strain M104. Overall, the most 'balanced' treatment against L. monocytogenes was CSC+M104+KE82. Hence, this starter/co-starter combination may be utilized in traditional Greek cheese technologies., (Copyright © 2016 Elsevier Ltd. All rights reserved.)