Mikrobiološka kvaliteta komercijalnog pekarskog kvasca na hrvatskom tržištu. (Bosnian)

Commercial baker's yeast is active biomass of yeast Saccharomyces cerevisiae. During production, distribution and storage it is joined by other microorganisms. In this work microbiological quality of samples of fresh and dried form of baker's yeast of different manufacturers present on the Croatian market has been researched. Classical microbiological methods were used for the isolation and identification of microbial populations in the samples of yeast. Microbial growth was determined by counting the colonies grown on the selective medium. The results showed that the dominant yeast contaminants were lactic acid bacteria (10⁵-10⁸ cells/g). Apart from them, wild yeasts (10³ cells/g) and coliform bacteria (10⁴ cells/g) were also detected. Dry yeast had a better microbiological quality while in those samples molds and Listeria monocytogenes were not detected. Salmonella and Escherichia coli were not detected in any sample, while Staphylococcus aureus was detected in 89% of fresh and 67% of dry yeast samples (101 cells/g). [ABSTRACT FROM AUTHOR]

Komercijalni pekarski kvasac je aktivna biomasa kvasca Saccharomyces cerevisiae kojoj se tijekom procesa proizvodnje, distribucije i skladištenja pridružuju i drugi nenamjenski mikroorganizmi. U radu je ispitana mikrobiološka kvaliteta uzoraka svježih i suhih oblika pekarskog kvasca različitih proizvođača prisutnih na hrvatskom tržištu. Za izolaciju i identifikaciju mikrobne populacije u uzorcima pekarskog kvasca upotrijebljene su klasične mikrobiološke metode, a mikrobni rast određen je brojanjem poraslih kolonija na selektivnim hranjivim podlogama. Rezultati su pokazali da su bakterije mliječne kiseline (BMK) dominantni pridruženi mikroorganizmi pekarskom kvascu, prisutni u koncentraciji od 10⁵ - 10⁸ st/g. U uzorcima kvasca dokazani su i divlji kvasci i koliformne bakterije u koncentraciji od 10³, odnosno 10⁴st/g. Suhi pekarski kvasac imao je bolju mikrobiološku kvalitetu budući da u uzorcima nisu dokazane plijesni i bakterija Listeria monocytogenes. Salmonella sp. i Escherichia coli nisu dokazane u nijednom uzorku, dok je Staphylococcus aureus dokazan u 89% uzoraka svježeg te 67% uzoraka suhog kvasca u koncentraciji od oko 10¹ st/g. [ABSTRACT FROM AUTHOR]

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