Pecorino Crotonese cheese: Study of bacterial population and flavour compounds

• Published in: Food microbiology Vol. 27; no. 3; pp. 363 - 374
• Main Authors: Randazzo, C.L., Pitino, I., Ribbera, A., Caggia, C.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.05.2010; Elsevier
• Subjects: Artisanal cheese; Bacteria; Bacterial population; Biological and medical sciences; capillary gas chromatography; Cheese - microbiology; cheese ripening; cheese starters; cheeses; Colony Count, Microbial; dairy farming; DNA, Bacterial - analysis; Electrophoresis, Agar Gel; flavor compounds; Flavour formation; Food industries; Food Microbiology; free fatty acids; Fundamental and applied biological sciences. Psychology; Gas Chromatography-Mass Spectrometry; Gram-Positive Bacteria - classification; Gram-Positive Bacteria - genetics; Gram-Positive Bacteria - growth & development; isolation; Lactobacillaceae - classification; Lactobacillaceae - growth & development; Lactobacillaceae - isolation & purification; Lactobacillus buchneri; Lactobacillus plantarum; Lactobacillus rhamnosus; Lactococcus lactis; Leuconostoc mesenteroides; mass spectrometry; microbial detection; microbial load; Milk and cheese industries. Ice creams; on-farm food safety; PCR-DGGE; Phylogeny; Polymorphism, Restriction Fragment Length; Polyphasic approach; Population Dynamics; pulsed-field gel electrophoresis; restriction fragment length polymorphism; RNA, Ribosomal, 16S - analysis; selective media; Species Specificity; Streptococcus thermophilus; Taste; traditional foods; traditional technology; volatile compounds; Volatilization; PCR-DGGE; Flavour formation; Bacterial population; Polyphasic approach; Artisanal cheese; Polymerase chain reaction; Dairy product; Cheese; Molecular biology; Flavor
• ISSN: 0740-0020; 1095-9998
• DOI: 10.1016/j.fm.2009.11.010

The diversity and dynamics of the dominant bacterial population during the manufacture and the ripening of two artisanal Pecorino Crotonese cheeses, provided by different farms, were investigated by the combination of culture-dependent and -independent approaches. Three hundred and thirty-three strains were isolated from selective culture media, clustered using Restriction Fragment Length Polymorphism and were identified by 16S rRNA gene sequencing. The results indicate a decrease in biodiversity during ripening, revealing the presence of Lactococcus lactis and Streptococcus thermophilus species in the curd and in aged cheese samples and the occurrence of several lactobacilli throughout cheese ripening, with the dominance of Lactobacillus rhamnosus species. Bacterial dynamics determined by Denaturant Gradient Gel Electrophoresis provided a more precise description of the distribution of bacteria, highlighting differences in the bacterial community among cheese samples, and allowed to detect Lactobacillus plantarum, Lactobacillus buchneri and Leuconostoc mesenteroides species, which were not isolated. Moreover, the concentration of flavour compounds produced throughout cheese ripening was investigated and related to lactic acid bacteria presence. Fifty-seven compounds were identified in the volatile fraction of Pecorino Crotonese cheeses by Gas Chromatography–Mass Spectrometry. Esters, alcohols and free fatty acids were the most abundant compounds, while aldehydes and hydrocarbons were present at low levels.