Skip to main content Accessibility help

Biological activity of the non-microbial fraction of kefir: antagonism against intestinal pathogens

  • Carolina Iraporda (a1) (a2), Mário Abatemarco Júnior (a3), Elisabeth Neumann (a3), Álvaro Cantini Nunes (a3), Jacques R Nicoli (a3), Analía G Abraham (a1) (a4) and Graciela L. Garrote (a1)...


Kefir is a fermented milk obtained by the activity of kefir grains which are composed of lactic and acetic acid bacteria, and yeasts. Many beneficial health effects have been associated with kefir consumption such as stimulation of the immune system and inhibition of pathogenic microorganisms. The biological activity of kefir may be attributed to the presence of a complex microbiota as well as the microbial metabolites that are released during fermentation. The aim of this work was to characterise the non-microbial fraction of kefir and to study its antagonism against Escherichia coli, Salmonella spp. and Bacillus cereus. During milk fermentation there was a production of organic acids, mainly lactic and acetic acid, with a consequent decrease in pH and lactose content. The non-microbial fraction of kefir added to nutrient broth at concentrations above 75% v/v induced a complete inhibition of pathogenic growth that could be ascribed to the presence of un-dissociated lactic acid. In vitro assays using an intestinal epithelial cell model indicated that pre-incubation of cells with the non-microbial fraction of kefir did not modify the association/invasion of Salmonella whereas pre-incubation of Salmonella with this fraction under conditions that did not affect their viability significantly decreased the pathogen's ability to invade epithelial cells. Lactate exerted a protective effect against Salmonella in a mouse model, demonstrating the relevance of metabolites present in the non-microbial fraction of kefir produced during milk fermentation.


Corresponding author

*For correspondence; e-mail:


Hide All
Alakomi, HL, Skytta, E, Saarela, M, Mattila-Sandholm, T, Latva-Kala, K & Helander, IM 2000 Lactic acid permeabilizes gram-negative bacteria by disrupting the outer membrane. Applied and Environmental Microbiology 66 20012005
Altier, C 2005 Genetic and environmental control of Salmonella invasion. Journal of Microbiology 43 8592
Arslan, S 2015 A review: chemical, microbiological and nutritional characteristics of kefir. CyTA-Journal of Food 13 340345
Barbosa, AF, Santos, PG, Lucho, AMS & Schneedorf, JM 2011 Kefiran can disrupt the cell membrane through induced pore formation. Journal of Electroanalytical Chemistry 653 6166
Beshkova, DM, Simova, ED, Frengova, GI, Simov, ZI & Dimitrov, ZHP 2003 Production of volatile aroma compounds by kefir stater cultures. International Dairy Journal 13 529535
Carpenter, CE & Broadbent, JR 2009 External concentration of acid anions and pH: key independent variables for studying how organic acids inhibit growth of bacteria in mildly acid foods. Journal of Food Science 74 1215
COBEA. Colégio Brasileiro de Experimentação Animal 2006. Legislação e Ética. (Accessed 1 March 2009)
Coconnier, MH, Lievin, V, Lorrot, M & Servin, AL 2000 Antagonistic activity of Lactobacillus acidophilus LB against intracellular Salmonella enterica serovar Typhimurium infecting human enterocyte-like Caco-2/TC- 7 cells. Applied and Environmental Microbiology 66 11521157
De Keersmaecker, SCJ, Verhoeven, TLA, Desair, J, Marchal, K, Vanderleyden, J & Nagy, I 2006 Strong antimicrobial activity of Lactobacillus rhamnosus GG against Salmonella typhimurium is due to accumulation of lactic acid. FEMS Microbiology Letters 259 8996
Garrote, GL, Abraham, AG & De Antoni, GL 2000 Inhibitory power of kefir: the role of organic acids. Journal of Food Protection 63 364369
Garrote, GL, Delfederico, L, Bibiloni, R, Abraham, AG, Pérez, PF, Semorile, L & De Antoni, G 2004 Lactobacilli isolated from kefir grains: evidence of the presence of S-layer proteins. Journal of Dairy Research 71 222230
Garrote, GL, Abraham, AG & De Antoni, GL 2010 Microbial interactions in kefir: a natural probiotic drink. In Biotechnology of Lactic Acid Bacteria, pp. 327340 of 393 (Eds Mozzi, F, Raya, R & Vignolo, M). Ames, USA: Blackwell Publishing. ISBN 978-0-8138-1583-1
Golowczyc, MA, Mobili, P, Garrote, GL, Abraham, AG & De Antoni, GL, 2007 Protective action of Lactobacillus kefir carrying S-layer protein against Salmonella enterica serovar Enteritidis. International Journal of Food Microbiology 118 264273
Guzel-Seydim, ZB, Seydim, AC, Greene, AK & Bodine, AB 2000 Determination of organic acids and volatile flavor substances in kefir during fermentation. Journal of Food Composition and Analysis 13 3543
Hamet, MF, Medrano, M, Pérez, PF & Abraham, AG 2016 Oral administration of kefiran exerts a bifidogenic effect on BALB/c mice intestinal microbiota. Beneficial microbes 7 237246
Hudault, S, Lievin, V, Bernet-Camard, MF & Servin, AL 1997 Antagonistic activity exerted in vitro and in vivo by Lactobacillus casei (strain GG) against Salmonella typhimurium C5 infection. Applied and Environmental Microbiology 63 513518
Iraporda, C, Romanin, DE, Rumbo, M, Garrote, GL & Abraham, AG 2014 The role of lactate on the immunomodulatory properties of the nonbacterial fraction of kefir. Food Research International 62 247253
Iraporda, C, Errea, AJ, Romanin, DE, Cayet, D, Pereyra, E, Pignataro, O, Sirard, JC, Garrote, GL, Abraham, AG & Rumbo, M 2015 Lactate and short chain fatty acids produced by microbial fermentation downregulate proinflammatory responses in intestinal epithelial cells and myeloid cells. Immunobiology 220 11611169
John, SM & Deeseenthum, S 2015 Properties and benefits of kefir–A review. Songklanakarin Journal of Science and Technology 37 275282
LeBlanc, J, Fliss, I & Matar, C 2004 Induction of a humoral immune response following an Escherichia coli O157:H7 infection with an immunomodulatory peptidic fraction derived from Lactobacillus helveticus-fermented milk. Clinical and Diagnostic Laboratory Immunology 11 11711181
Londero, A, Iraporda, C, Garrote, GL & Abraham, AG 2015 Cheese whey fermented with kefir micro-organisms: antagonism against Salmonella and immunomodulatory capacity. International Journal of Dairy Technology 68 118126
Makras, L, Triantafyllou, V, Fayol-Messaoudi, D, Adriany, T, Zoumpopoulou, G, Tsakalidou, E, Servinc, A & De Vuysta, L 2006 Kinetic analysis of the antibacterial activity of probiotic lactobacilli towards Salmonella enterica serovar Typhimurium reveals a role for lactic acid and other inhibitory compounds. Research in Microbiology 157 241247
Piermaria, JA, Mariano, L & Abraham, AG 2008 Gelling properties of kefiran, a food-grade polysaccharide obtained from kefir grain. Food Hydrocolloids 22 15201527
Powell, JE, Witthuhn, RC, Todorov, SD & Dicks, LMT 2007 Characterization of bacteriocin ST8KF produced by a kefir isolate Lactobacillus plantarum ST8KF. International Dairy Journal 17 190198
Presser, KA, Ratkowsky, DA & Ross, T 1997 Modelling the growth rate of Escherichia coli as a function of pH and lactic acid concentration. Applied and Environmental Microbiology 63 23552360
Rimada, PS & Abraham, AG 2001 Polysaccharide production by kefir grains during whey fermentation. Journal of Dairy Research 68 653661
Southgate, DA 1976 Selected Methods In Determination of Food Carbohydrates, pp. 99144. Essex, UK: Applied Science Publishers Ltd
Tejero-Sariñena, S, Barlow, J, Costabile, A, Gibson, GR & Rowland, I 2012 Pathogenesis and toxins. In vitro evaluation of the antimicrobial activity of a range of probiotics against pathogens: evidence for the effects of organic acids. Anaerobe 18 530538
Tellez, A, Corredig, M, Turner, PV, Morales, R & Griffiths, M 2011 A peptidic fraction from milk fermented with Lactobacillus helveticus protects mice against Salmonella infection. International Dairy Journal 21 607614
Tsilingiri, K, Barbosa, T, Penna, G, Caprioli, F, Sonzogni, A, Viale, G & Rescigno, M 2012 Probiotic and postbiotic activity in health and disease: comparison on a novel polarized ex-vivo organ culture model. Gut 61 10071015
Vinderola, G, Perdigon, G, Duarte, J, Thangavel, D, Farnworth, E & Matar, C 2006 Effects of kefir fractions on innate immunity. Immunobiology 211 149156
Zagato, E, Mileti, E, Massimiliano, L, Fasano, F, Budelli, A, Penna, G & Rescigno, M 2014 Lactobacillus paracasei CBA L74 metabolic products and fermented milk for infant formula have anti-Inflammatory activity on dendritic cells in vitro and protective effects against colitis and an enteric pathogen in vivo. PLoS ONE 9 87615
Zajšek, K, Kolar, M & Goršek, A 2011 Characterisation of the exopolysaccharide kefiran produced by lactic acid bacteria entrapped within natural kefir grains. International Journal of Dairy Technology 64 544548


Type Description Title
Supplementary materials

Iraporda et al supplementary material
Iraporda et al supplementary material

 PDF (367 KB)
367 KB

Biological activity of the non-microbial fraction of kefir: antagonism against intestinal pathogens

  • Carolina Iraporda (a1) (a2), Mário Abatemarco Júnior (a3), Elisabeth Neumann (a3), Álvaro Cantini Nunes (a3), Jacques R Nicoli (a3), Analía G Abraham (a1) (a4) and Graciela L. Garrote (a1)...


Altmetric attention score

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed