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Milk Kefir: Ultrastructure, Antimicrobial Activity and Efficacy on Aflatoxin B1 Production by Aspergillus flavus

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Abstract

The association of kefir microbiota was observed by electron microscopic examination. Scanning electron microscopic (SEM) observations revealed that kefir grain surface is very rough and the inner portions had scattered irregular holes on its surface. The interior of the grain comprised fibrillar materials which were interpreted as protein, lipid and a soluble polysaccharide, the kefiran complex that surrounds yeast and bacteria in the grain. Yeast was observed more clearly than bacteria on the outer portion of the grain. Transmission electron microscopic (TEM) observations of kefir revealed that the grain comprised a mixed culture of yeast and bacteria growing in close association with each other. Microbiota is dominated by budded and long-flattened yeast cells growing together with lactobacilli and lactococci bacteria. Bacterial cells with rounded ends were also observed in this mixed culture. Kefir grains, kefir suspensions, and kefiran were tested for antimicrobial activities against several bacterial and fungal species. The highest activity was obtained against Streptococcus faecalis KR6 and Fusarium graminearum CZ1. Growth of Aspergillus flavus AH3 producing for aflatoxin B1 for 10 days in broth medium supplemented with varying concentrations of kefir filtrate (%, v/v) showed that sporulation was completely inhibited at the higher concentrations of kefir filtrate (7–10%, v/v). The average values of both mycelial dry weights and aflatoxin B1 were completely inhibited at 10% (v/v). This is the first in vitro study about the antifungal characteristics of kefir against filamentous fungi which was manifested by applying its inhibitory effect on the productivity of aflatoxin B1 by A. flavus AH3.

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References

  1. Basappa SC, Sreenivasamurthy V, Parpia HA (1970) Aflatoxin and kojic acid production by resting cells of Asergillus flavus Link. J Gen Microbiol 61:81–86

    PubMed  CAS  Google Scholar 

  2. Blanco JL, Carrion BA, Liria N, Diaz S, Garcia ME, Dominguz L, Suarez G (1993) Behavior of aflatoxins during manufacture and storage of yoghurt. Milchwissenschaft 48:385–387

    CAS  Google Scholar 

  3. Bonadè A, Murelli F, Vescovo M, Scolari G (2001) Partial characterization of a bacteriocin produced by Lactobacillus helveticus. Lett Appl Microbiol 33:153–158

    Article  PubMed  Google Scholar 

  4. Coker RD (1995) Controlling mycotoxins in oilseeds and oilseed cakes. Chem Ind 7:260–264

    Google Scholar 

  5. Criseo G, Bagnara A, Bisignano G (2001) Differentiation of aflatoxin-producing and non-producing strains of Aspergillus flavus group. Lett Appl Microbiol 33:291–295

    Article  PubMed  CAS  Google Scholar 

  6. Dada LO, Muller HG (1983) The fate of aflatoxin B1 in the production of Ogi, Nigerian fermented sorghum porridge. J Cereal Sci 1:63–70

    Article  CAS  Google Scholar 

  7. Diniz RO, Garla LK, Schneedorf JM, Carvalho JCT (2003) Study of anti-inflammatory activity of Tibetan mushroom, a symbiotic culture of bacteria and fungi encapsulated into a polysaccharide matrix. Pharmacol Res 47(1):49–52

    Article  PubMed  CAS  Google Scholar 

  8. Domsch KH, Gaws W, Anderson TH (1980) Compendium of soil fungi. vol 1. Academic press, London

    Google Scholar 

  9. Dubois M, Gilles K, Hamilton J, Robers PA, Smith F (1956) Colometric method for determination of sugars and related substances. Anal Chem 28(2):350–356

    Article  CAS  Google Scholar 

  10. Farnworth ER (2006) Kefir—a complex probiotic. Food Sci Technol Bull Funct Foods 2:1–17

    Article  Google Scholar 

  11. Frengova GI, Simova ED, Beshkova DM, Simov ZI (2002) Exopolysaccharides produced by lactic acid bacteria of kefir grains. Z Naturforsch C 57(9-10):805–810

    PubMed  CAS  Google Scholar 

  12. Garrote GL, Abraham AG, De Antoni GL (1997) Preservation of kefir grains, a comparative study. Lebensm Wiss Technol 30:77–84

    Article  CAS  Google Scholar 

  13. Güzel-Seydim Z, Wyffels JT, Seydim AC, Greene AK (2005) Turkish kefir and kefir grains: microbial enumeration and electron microscopic observation. Int J Dairy Technol 58(1):25–29

    Article  Google Scholar 

  14. Hallé C, Leroi F, Dousset X, Pidoux M (1994) Les kéfirs: des associations bactéries-levures. In: de Roissart H, Luquet FM (eds) Bactéries lactiques, vol 2. Lorica, Uriage, pp 169–182 (in French)

    Google Scholar 

  15. Harley MM, Fergusen IK (1990) The role of SEM in pollen morphology and plant systematic. In: Claugher D (ed) Scanning electron microscope in taxonomy and functional morphology. Systematics association special, vol 41. Clarendon Press, Oxford, pp 45–68

  16. Jamuna M, Jeevaratnam K (2004) Isolation and characterization of lactobacilli from some traditional fermented foods and evaluation of the bacteriocins. J Gen Appl Microbiol 50:79–90

    Article  PubMed  CAS  Google Scholar 

  17. Kaufmann K (1997) Kefir rediscovered. Alive Book, Burnahy

    Google Scholar 

  18. Kwon CS, Park MY, Cho JS, Choi ST, Chang DS (2003) Identification of effective microorganisms from kefir fermented milk. Food Sci Biotechnol 12:476–479

    Google Scholar 

  19. Libudzisz Z, Piatkiewicz A (1990) Kefir production in Poland. Dairy Ind Int 55:31–33

    Google Scholar 

  20. Liu J-R, Lin C-W (2000) Production of kefir from soymilk with or without added glucose, lactose or sucrose. J Food Sci 65:716–719

    Article  CAS  Google Scholar 

  21. Lopitz-Otsoa F, Rementeria A, Elguezabal N, Garaizar J (2006) Kefir: a symbiotic yeasts-bacteria community with alleged healthy capabilities. Rev Iberoam Micol 23(2):67–74

    Article  PubMed  Google Scholar 

  22. Luft JH (1961) Improvements in epoxy resin embedding methods. J Biophys Biochem Cytol 9:409–414

    Article  PubMed  CAS  Google Scholar 

  23. Marshall VM, Cole WM, Brooker BE (1984) Observations on the structure of kefir grain and the distribution of the microflora. J Appl Bacteriol 57:491–497

    Google Scholar 

  24. Messens W, De Vuyst L (2002) Inhibitory substances produced by Lactobacilli isolated from sourdoughs-a review. Int J Food Microbiol 72:31–43

    Article  PubMed  CAS  Google Scholar 

  25. Moubasher AH (1993) Soil fungi in Qatar and other Arab countries. The Centre for Scientific and Applied Research, Doha

    Google Scholar 

  26. Nout MJR (1994) Fermented foods and food safety. Food Res Int 27:291–298

    Article  CAS  Google Scholar 

  27. Onilude AA, Fagade OE, Bello MM, Fadahunsi IF (2005) Inhibition of aflatoxin- producing aspergilli by lactic acid bacteria isolated from indigenously fermented cereal gruels. Afr J Biotechnol 4(12):1404–1408

    CAS  Google Scholar 

  28. Pitt JI (2000) Toxigenic fungi: which are important? Med Mycol 38(Suppl 1):17–22

    PubMed  Google Scholar 

  29. Reynolds ES (1963) The use of lead citrate at high pH as an electron opaque stain in electron microscopy. J Cell Biol 17:207–212

    Article  Google Scholar 

  30. Rodrigues KL, Caputo LRG, Carvalho JCT, Evangelista J, Schneedorf JM (2005) Antimicrobial and healing activity of kefir and kefiran extract. Int J Antimicrob Agents 25:404–408

    Article  PubMed  CAS  Google Scholar 

  31. Schneedorf JM, Anfiteatro D (2004) Fitoterapicos anti-inflamatorios by Carvalho, JCT. Quefir, um probiotico produzido por microorganismos encapsulados e inflamacao. Chap 33, pp 443–462

    Google Scholar 

  32. Serot T, Dousset X, Zucca J, Torcatis N (1990) Mise en évidence et purification partielle de substances antibacteriennes produites par Leuconostoc mesenteroides et Lactobacillus plantarum isoles de grains de kéfyr. Microbiol Aliments Nutr 8:71–76

    CAS  Google Scholar 

  33. Snedecor GW, Cochran WG (1967) Statistical methods. The Iowa State University Press, Ames

    Google Scholar 

  34. Sptempack JG, Ward RT (1964) An improved staining method for electron microscopy. J Cell Biol 22:679–701

    Google Scholar 

  35. Vanne L, Kleemola T, Haikara A (2000) Screening of the antifungal effects of lactic acid bacteria against toxigenic Penicillium and Aspergillus strains in http://www.vtt./bel/2000microbiology/antifungalattributesoflacticacidbacteria./

  36. Wayne PA (2002) Performance standards for antimicrobial disk susceptibility test. Approved standard M2-A6. 6th edn. National Committee for Clinical Laboratory Standards (NCCLS), Wayne

  37. Westby A, Reilly A, Bainbridge Z (1997) Review of the effect of fermentation on naturally occurring toxins. Food Control 8(5/6):329–339

    Article  Google Scholar 

  38. Yüksekdag ZN, Beyatli Y, Aslim B (2004) Determination of some characteristics coccoid forms of lactic acid bacteria isolated from Turkish kefir with natural probiotic. Lebensm Wiss Technol 37:663–667

    Google Scholar 

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Acknowledgments

We thank the technicians of the Central Laboratory of Electron Microscope, Faculty of Science, Zagazig University, Egypt for performance of the processing steps of SEM and TEM.

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  1. Department of Botany and Microbiology, Faculty of Science, Zagazig University, Zagazig, Egypt

    Ahmed A. Ismaiel, Mohamed F. Ghaly & Ayman K. El-Naggar

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  1. Ahmed A. Ismaiel
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  2. Mohamed F. Ghaly
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  3. Ayman K. El-Naggar
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Correspondence to Ahmed A. Ismaiel.

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Ismaiel, A.A., Ghaly, M.F. & El-Naggar, A.K. Milk Kefir: Ultrastructure, Antimicrobial Activity and Efficacy on Aflatoxin B1 Production by Aspergillus flavus . Curr Microbiol 62, 1602–1609 (2011). https://doi.org/10.1007/s00284-011-9901-9

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