title: Influence of PDO Ragusano cheese biofilm microbiota on flavour compounds formation.
abstract: The objectives of the present study were to characterize the biofilm microbiota of 11 different farms (from A to K), producing PDO Ragusano cheese, and to investigate on its ability to generate volatile organic compounds (VOCs) in milk samples inoculated with biofilm and incubated under Ragusano cheese making conditions. The biofilms were subjected to plate counting and PCR/T/DGGE analysis and the VOCs generated in incubated milk samples were evaluated through SmartNose, GC/O, and GC/MS. Streptococcus thermophilus was the dominant species both in biofilms and in incubated milks. Lactobacillus, Lactococcus, Enterococcus and Leuconostoc were also identified. Low levels of Pseudomonas spp. and yeasts counts were detected, whereas coliforms, Listeria monocytogenes and Salmonella spp., were never found. SmartNose and GC/O analyses were able to differentiate incubated milk samples on the basis of the odour compounds, highlighting that samples E and F overlapped and sample C was clearly separated from the others. These results complied with those acquired by GC/MS analysis, that detected in total 20 VOCs. Principal component analysis showed positive correlations (r > 0.6; P < 0.05) between some lactic acid bacteria (LAB) and VOCs: such as Enterococcus hirae with alcohols, Lactococcus lactis, Lactobacillus plantarum, Lactobacillus casei and Lactobacillus delbrueckii with aldehydes, and Lactobacillus fermentum, Lactobacillus helveticus and Lactobacillus hilgardii with ketones. This work demonstrates that biofilm represents an excellent source of LAB biodiversity, which contribute to generate VOCs during the production of PDO Ragusano cheese.
authors.affiliation: CoRFiLaC, Regione Siciliana, 97100 Ragusa, Italy.
authors.forename: Stefania
authors.initials: S
authors.lastname: Carpino
authors.affiliation: Department of Agricultural, Food and Environment, University of Catania, via Santa Sofia 98, 95124 Catania, Italy. Electronic address: cranda@unict.it.
authors.forename: Cinzia L
authors.initials: CL
authors.lastname: Randazzo
authors.affiliation: Department of Agricultural, Food and Environment, University of Catania, via Santa Sofia 98, 95124 Catania, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Pino
authors.affiliation: CoRFiLaC, Regione Siciliana, 97100 Ragusa, Italy.
authors.forename: Nunziatina
authors.initials: N
authors.lastname: Russo
authors.affiliation: CoRFiLaC, Regione Siciliana, 97100 Ragusa, Italy.
authors.forename: Teresa
authors.initials: T
authors.lastname: Rapisarda
authors.affiliation: CoRFiLaC, Regione Siciliana, 97100 Ragusa, Italy.
authors.forename: Gianni
authors.initials: G
authors.lastname: Belvedere
authors.affiliation: Department of Agricultural, Food and Environment, University of Catania, via Santa Sofia 98, 95124 Catania, Italy.
authors.forename: Cinzia
authors.initials: C
authors.lastname: Caggia
mesh_terms: D000818:Animals; D001419:Bacteria / Q000235:genetics / Q000302:isolation & purification; D044822:Biodiversity; D018441:Biofilms; D002611:Cheese / Q000382:microbiology*; D015169:Colony Count, Microbial; D005516:Food Microbiology; D007777:Lactobacillaceae / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology; D008089:Listeria monocytogenes / Q000235:genetics / Q000302:isolation & purification; D064307:Microbiota / Q000502:physiology; D008892:Milk / Q000382:microbiology; D016133:Polymerase Chain Reaction; D012475:Salmonella / Q000235:genetics / Q000302:isolation & purification; D048249:Streptococcus thermophilus / Q000235:genetics / Q000302:isolation & purification; D013649:Taste; D055549:Volatile Organic Compounds / Q000032:analysis / Q000378:metabolism*; D014934:Wood / Q000382:microbiology
chemical_list: D055549:Volatile Organic Compounds
keywords: GC/MS; LAB; PCR/DGGE; SmartNose; Tina biofilm; Traditional cheese