UV-C-inactivation of microorganisms in naturally cloudy apple juice using novel inactivation equipment based on Dean vortex technology

Autor: Volker Graef, Gyu-Sung Cho, Mario Stahl, Ingrid Specht, Charles M. A. P. Franz
Rok vydání: 2009
Předmět:
Zdroj: Food Control. 20:1103-1107
ISSN: 0956-7135
Popis: A novel UV-C irradiation device in laboratory scale was tested for its potential to inactivate bacteria in naturally cloudy apple juice. In this device, liquid flows through a helically wound tubing wrapped around a quartz glass tube containing a 9 W UV lamp with an irradiation intensity of 60 W/m2 at 254 nm. The equipment was capable of reducing numbers of inoculated Escherichia coli and Lactobacillus brevis from an initial concentration of approximately 106 CFU/ml or 104 CFU/ml to below detectable limits in commercial naturally cloudy apple juice at a flow rate of 2 l/h, and to well below 1 × 102 also at higher flow rates of 4 and 8 l/h. Numbers of Saccharomyces cerevisiae could be reduced from an initial level of ca. 1 × 104–1 × 102 CFU/ml or less at flow rates of 2 and 4 l/h. Although E. coli could be effectively inactivated also in self-extracted, as well as industrially processed apple juice, contaminating yeast and lactic acid bacteria were not completely eliminated.
Databáze: OpenAIRE