Lactobacillus acidophilus NCFM Survival in Acidified Yogurts

Lactic acid bacteria;acid resistance;yogurt;Lactobacillus acidophilus;probiotics

Trahan, Caitlin Elizabeth ; Dr. Ilenys M. Perez-Diaz, Committee Member,Dr. Trevor G. Phister, Committee Co-Chair,Dr. Todd R. Klaenhammer, Committee Chair,Trahan, Caitlin Elizabeth ; Dr. Ilenys M. Perez-Diaz ; Committee Member ; Dr. Trevor G. Phister ; Committee Co-Chair ; Dr. Todd R. Klaenhammer ; Committee Chair

University:North Carolina State University

关键词: Lactic acid bacteria;    acid resistance;    yogurt;    Lactobacillus acidophilus;    probiotics;   

Others  :  https://repository.lib.ncsu.edu/bitstream/handle/1840.16/1296/etd.pdf?sequence=1&isAllowed=y

美国|英语

来源: null

【 摘 要 】

Lactobacillus acidophilus NCFM is a probiotic culture widely added to dairy products and dietary supplements.The bacterium has been linked with immune modulation, cold prevention in humans, and relief of gut pain via a morphine like mechanism in animals.Industrially, the target for delivery of viable cells in a 6 oz. serving of yogurt at the end of a 52 day shelf-life is 2 x 106 CFU/g.Survival studies with an industrial yogurt formulation showed that counts of NCFM fell to less than 102 CFU/g at the end of shelf-life.The objective of this study was to investigate the reasons for the dramatic loss of viability during shelf-life, and define a solution that could maintain viability throughout shelf-life.Levels of NCFM were followed in fermented yogurts at pH 4.1, 4.7 and 5.0.Results showed that with inoculation levels of 108 CFU/ml, NCFM added at the outset of fermentation maintained survival in yogurts acidified at pH 4.7 and 5.0.NCFM showed poor survival in yogurts acidified to pH 4.1, exhibiting a 3 log loss after 48 days.The possible effects of cell injury in lyophilized Lb. acidophilus NCFM cells were also investigated.Cells subjected to a 60 minute resuscitation period in MRS media, prior to addition to acidified yogurt base at pH 4.1, showed only a ~1.5 log loss after 42 days.Survival of NCFM in yogurt was compromised at acidic conditions below pH 4.7 and a recovery period of the lyophilized cells can greatly improve survival.