Survival of some food-borne bacteria in kefir produced by microbial levan and pullulan  

作　　者：Gökhan Gurur Gökmen Jaroslaw Kowalik Duygu Kışla 

机构地区：[1]Department of Food Engineering,Faculty of Engineering,Ege University,35100,Bornova,Izmir,Turkey [2]Department of Dairy Science and Quality Management,Faculty of Food Sciences,University of Warmia and Mazury in Olsztyn,Oczapowskiego str.7,10-719,Olsztyn,Poland

出　　处：《Food Bioscience》2022年第3期1082-1089,共8页食品生物科学（英文）

摘　　要：Kefir is a fermented milk product produced by kefir grains traditionally or lyophilized starter culture.Some quality characteristics of kefir produced at 22℃ and 30℃ using kefir grains after addition of microbial levan and pullulan were investigated for 14 days.Additionally,the survival of different Gram-positive and Gram-negative bacteria strains which were inoculated before and after fermentation were investigated during storage.The pH and titratable acidity were in the ranges of 4.67–4.39 and 1.10–0.87%,respectively.The highest exopolysaccharide values(458.3–465.3 mg/kg)were found in the samples produced with the addition of 1%(w/v)of microbial levan at 30℃.Yeast counts were in the ranges of 6.73–5.11 log CFU/mL while the lactobacilli and lactic streptococci counts were in the ranges of 9.64–7.91 and 9.64–8.69 log CFU/mL,respectively.The microbial polysaccharide addition did not show any significant differences in the enumeration of lactic acid bacteria in kefir(p>0.05).All Gram-positive and Gram-negative bacteria grew/survived during fermentation however Listeria monocytogenes was the most susceptible test bacterium to metabolites during storage.The highest reduction in the counts of L.monocytogenes was determined as 2.39 log units after 24 h of fermentation at 30℃ in the samples which were inoculated before fermentation and produced with the addition of pullulan.Kefir samples produced at 30℃ without polysaccharide addition were considered as the best with respect to appearance,taste,consistency and overall acceptability.

关 键 词：Kefir grain LEVAN PULLULAN Food-borne bacteria 

分 类 号：TS201.3[轻工技术与工程—食品科学]