title: Effect of stress pretreatment on survival of probiotic bacteria in gastrointestinal tract simulator.
abstract: The effect of stress pretreatment on survival of probiotic Lactobacillus acidophilus La-5, Lactobacillus rhamnosus GG, and Lactobacillus fermentum ME-3 cultures was investigated in the single bioreactor gastrointestinal tract simulator (GITS). The cultures were pregrown in pH-auxostat, subjected to temperature, acid, or bile stress treatment, fast frozen in liquid nitrogen (LN(2)), and tested for survival in GITS. After LN(2) freezing the colony forming ability of L. rhamnosus GG and L. fermentum ME-3 nonstressed and stressed cells was well retained (average survival of 75.4 +/- 18.3% and 88.0 +/- 7.2%, respectively). L. acidophilus La-5 strain showed good survival of auxostat nonstressed cells after fast freezing (94.2 +/- 15.0), however the survival of stress pretreated cells was considerably lower (30.8 +/- 8.5%). All LN(2) frozen auxostat cultures survived well in the acid phase of the GIT simulation (survival 81 +/- 21%); however, after the bile phase, the colony formation ability of L. acidophilus La-5, L. rhamnosus GG, and L. fermentum ME-3 decreased by approximately 1.4 +/- 0.2, 3.8 +/- 0.3, and 3.5 +/- 1.2 logarithmic units, respectively. No statistically relevant positive effect of stress pretreatments on survival of LN(2) frozen L. acidophilus La-5, L. rhamnosus GG, and L. fermentum ME-3 in GITS was observed.
authors.affiliation: Competence Centre of Food and Fermentation Technologies, Akadeemia tee 15b, 12618, Tallinn, Estonia.
authors.forename: Ingrid
authors.initials: I
authors.lastname: Sumeri
authors.forename: Liisa
authors.initials: L
authors.lastname: Arike
authors.forename: Jelena
authors.initials: J
authors.lastname: Stekolstsikova
authors.forename: Riin
authors.initials: R
authors.lastname: Uusna
authors.forename: Signe
authors.initials: S
authors.lastname: Adamberg
authors.forename: Kaarel
authors.initials: K
authors.lastname: Adamberg
authors.forename: Toomas
authors.initials: T
authors.lastname: Paalme
mesh_terms: D001647:Bile Acids and Salts / Q000494:pharmacology; D019149:Bioreactors; D015169:Colony Count, Microbial; D005615:Freezing; D041981:Gastrointestinal Tract / Q000382:microbiology*; D006863:Hydrogen-Ion Concentration; D007778:Lactobacillus / Q000254:growth & development*; D007779:Lactobacillus acidophilus / Q000254:growth & development; D052197:Limosilactobacillus fermentum / Q000254:growth & development; D050296:Microbial Viability; D019936:Probiotics; D013312:Stress, Physiological
chemical_list: D001647:Bile Acids and Salts