Naslov
Monitoring of lactococcal community’s size in Istrian cheese by culture dependent and culture independent methods

Autori
Mrkonjić Fuka, Mirna ; Skelin, Andrea ; Redžepović, Sulejman ; Trmčić, Aljoša

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, ostalo

Izvornik
Book of abstracts, 7th International Congress of Food Technologists, Biotechnologists and Nutritionists / Helga Medić - Zagreb, 2011, 66-66

ISBN
978-953-99725-3-8

Skup
7th International Congress of Food Technologists, Biotechnologists and Nutritionists

Mjesto i datum
Opatija, Hrvatska, 20.09.2011. - 23.09.2011

Vrsta sudjelovanja
Poster

Vrsta recenzije
Nije recenziran

Ključne riječi
Istrian cheese; lactococci; real-time PCR; CFU

Sažetak
Introduction: Istrian cheese is a traditional Croatian dairy product that is prepared from raw ewe’s milk without application of starter cultures such allowing for spontaneous fermentation. Lactococci contribute significantly to the microbial processes of Istrian cheese. Molecular based analyses have shown that the biodiversity of different food ecosystems is still unknown. This lack of knowledge is mostly attributed to the failure of many bacteria to grow in a given culture medium. Although we gained basic information on most abundant microbial groups in Istrian cheese based on CFU count, real Time PCR is more sensitive and could reached microflora that are not able to grow on selective media. Thus, the objective of this study was to quantitatively investigate dynamic of lactococci in Istrian cheese during the ripening by culture dependent and independent methods. Methodology: Milk and cheese samples were collected from two independent manufactures (F1 and F2). Milk (M) and fresh cheeses (Ch0) were taken at day zero ; cheese samples were sampled after 30 (Ch30), 60 (Ch60), 90 (Ch90) and 120 (Ch120) days. Isolation and enumeration of lactococci was done on M17 agar at 30°C. Total DNA was extracted and purified using the Maxwell Tissue DNA Purification Kit and proceeded to real-time PCR analysis. Results and discussion: The number of lactococci increased during the ripening and was between 5.49 (milk) and 8.67 (Ch120). Similar pattern was observed when estimating number of lactococci by real-time PCR and CFU method. However, the number of lactococci was approximately one order of magnitude greater when applying real-time PCR analysis. Conclusion: Our results indicate main changes in lactococcal community' size during the ripening process. Similar pattern was observed when estimating number of lactococci by culture dependent and independent methods. Real-time PCR is powerful and rapid tool to monitor in situ bacterial dynamic in cheese ecosystem.

Izvorni jezik
Engleski

Znanstvena područja
Poljoprivreda (agronomija), Biotehnologija

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