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SummaryRetardation of microbial spoilage of bread can be achieved by the use of spontaneous sourdough with an antimicrobial activity. This study was undertaken to identify lactic acid bacteria naturally occurring in spontaneous sourdough and use them for quality improvement and prolonging shelf life of rye, wheat and rye with wheat bread. Identifi cation of isolates from spontaneous sourdough by pyrosequencing assay showed that Lactobacillus reuteri were dominant lactic acid bacteria. The isolates showed a wide range of antimicrobial activity and displayed a synergistic activity against other lactobacilli, some lactococci and foodborne yeasts. The best application of spontaneous sourdough was noticed in the rye bread with the lowest crumb fi rmness of the fi nal product, although the sensory results of wheat and rye with wheat bread did not statistically diff er from control bread. L. reuteri showed a high preserving capacity against fungi during storage. This may be due to bacteriocins and various fatt y acids secreted into the growth medium that were identifi ed by agar well diff usion assay and gas chromatography. L. reuteri showing high antimicrobial activity have the potential to be used as a starter additive that could improve safety and/or shelf life of bread.

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The aim of the study was to determine the impact of residues of detergents and disinfectants on the results of most commonly used inhibitor tests for raw milk. Microbiological test (Delvotest SP-NT) and three rapid tests (Charm 3 MRL BL/TET2, Charm ROSA MRL BL/TET and Penzym) were used in the study. Three concentrations (recommended by the manufacturer, 10 times lower and twice higher) of 36 detergents and disinfectants in raw milk were investigated. All methods did not detect concentrations of detergents and disinfectants of alkaline and acid origin 10 times lower than recommended by the manufacturer. 39% of the investigated substances of alkaline origin were detected by Delvotest SP-NT and Penzym; Charm tests showed non-typical results only. Delvotest SP-NT did not detect substances of acid origin; Penzym detected 50% of these substances, Charm tests show abstract