Abstract:The hop pellets might be contaminated by microorganism during processing and storage，thereby increased the risk of contaminating the dry adding hop process.In order to study the effect of hops microorganisms on beer fermentation，three strains of Y1，Y2 and Y4 were isolated from commonly used dried hop particles.According to morphological observation，physiological and biochemical identification and phylogenetic tree，Y1 was identified as Bacillus velezensis，Y2 was Terribacillus saccharophilus，Y4 was Bacillus sp..According to the number of colonies in hops，Y1，Y2 and Y4 were put into beer.It was found that all the three strains could change the flavor of beer.When Y2 was added，the total acid content of beer increased the most，reaching 2.2 mL/100 mL，which was 32% higher than the blank group.Y2 bacteria increased beer total alcohol by 33.23%，and Y4 strain increased the total ester most，which increased by 54.23%.Bacillus and Terribacillus in hops could increase beer biogenic amines，and the effects of different strains were not the same.The results showed that the microorganisms selected from the hop particles was bacteria，mainly Bacillus and Terribacillus.The metabolism of these bacteria in beer fermentation broth could change the flavor and biogenic amine content of beer.This showed that if hop granules was not sterilized，the dry adding hop process had certain risks to the biological stability of beer.