Genetic characterization of some lactic acid bacteria occurring in an artisanal protected denomination origin (PDO) Italian cheese, the Toma piemontese
Articolo
Data di Pubblicazione:
2003
Citazione:
Genetic characterization of some lactic acid bacteria occurring
in an artisanal protected denomination origin (PDO)
Italian cheese, the Toma piemontese / M.G. Fortina, G. Ricci, A. Acquati, G. Zeppa, A. Gandini, P.L. Manachini. - In: FOOD MICROBIOLOGY. - ISSN 0740-0020. - 20:4(2003), pp. 397-404. [10.1016/S0740-0020(02)00149-1]
Abstract:
We studied the natural bacterial population used in the production of artisanal protected denomination origin (PDO) Toma
piemontese cheese in order to obtain preliminary information on the lactic acid bacteria involved in the traditional fermentation of
this cheese. A total of 116 coccal isolates and 11 mesophilic lactobacilli were collected from different curd and cheese samples, and
were identified by the combined use of PCR 16S–23S rDNA spacer analyses, species-specific probes and 16S rDNA sequencing. The
results obtained were supported by DNA/DNA hybridization studies and by reference cultures used as markers. Lactococci
constituted 67% of the coccal isolates. They were identified as Lactococcus lactis and L. garvieae, with an incidence of this latter
species higher than expected. The majority of these lactococcal isolates displayed an atypical phenotype of growing in the presence
of 6.5% NaCl and at 101C. Enterococci were also isolated, principally from the cheese samples (16% of the coccal isolates), together
with strains of Streptococcus macedonicus and S. thermophilus, the latter in a lower amount. Lactobacilli (principally Lactobacillus
paracasei strains) were only detected in three samples and their incidence was very low ( 1, 3 and 7 cfu g–1, respectively). The presence
of undesirable micro-organisms in some samples of curd emphasizes the necessity of improving the general hygienic conditions of
cheese production. The results suggest the possibility of preserving the wild bacterial population in order to protect the typical
organoleptic characteristics of this traditional raw milk cheese and to select new strains for the dairy industry.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
Bacterial identification; Lactic acid bacteria; Species-specific PCR; Toma cheese
Elenco autori:
M.G. Fortina, G. Ricci, A. Acquati, G. Zeppa, A. Gandini, P.L. Manachini
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