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FAYEMI, OLANREWAJU EMMANUEL (Ph.D)mtu.edu.ng/mtu/oer/conferences/31-Diary conference... ·...

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  • Presented

    By

    FAYEMI, OLANREWAJU EMMANUEL (Ph.D)

    at

    South African Society of Dairy Technology 46th Annual GeneralMeeting and Symposium on Food Safety and Security: A dairyperspective. (16th – 19th April, 2013), Khaya Ibhubesi, Parys FreeState, South Africa

    The effect of probiotic bacteria on environmental E. coli strains in fermented goat’s milk by FAYEMI, OLANREWAJU

    EMMANUEL (Ph.D) is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

    http://creativecommons.org/licenses/by-nc/4.0/http://creativecommons.org/licenses/by-nc/4.0/http://creativecommons.org/licenses/by-nc/4.0/

  • The effect of probiotic bacteriaon environmental E. coli strainsin fermented goat’smilk

    - FAYEMI, O. E (Ph.D)

  • • E. coli strains are non-pathogenic members of the

    intestinal microbiota of humans and other animals, but some

    acquired virulence factors that enable them to cause important

    intestinal and extra intestinal diseases, such as diarrhoea,

    hemorrhagic colitis (HC), and haemolytic uremic syndrome

    (HUS)

    • Diarrhoea disease is a major cause of morbidity and

    mortality in children aged five and below in most low-and-

    middle income countries (Olatunde et al. 2011)

    Introduction

  • • In 2009, UNICEF and WHO reported that one in

    five child deaths (about 1.5 million) each year is due to

    diarrhoea. It kills more young children than AIDS,

    malaria and measles combined

    • According to Carey et al. (2008), the majority of

    the outbreaks of diarrhoea are associated with water and

    food.

    • In many rural areas of South Africa, village

    communities depend on untreated water from wells,

    rivers, and other surface-water for drinking and food

    processing (Pascal, 2009)

  • • Acidification is a treatment commonly used to control growth

    or kill pathogenic microorganisms in foods

    • Implication of fermented foods in food-borne outbreaks

    caused by E. coli.

    • Several studies have been done to determine the mechanism

    of acid–adaptation and acid resistance in E. coli systems

    (Dlamini and Buys, 2009)

    Acid Resistance in E. coli

  • • Eli Metchnikoff hypothesis

    Problem Statement

    • If the extended survival of E. coli in acidic foods cannot be

    dismissed, then What will be the effects of probiotic

    bacteria on the growth of E. coli in fermented goat’s milk

    product?

  • • The lower buffering capacity of

    goat’s milk when compared with that of

    cow milk may allow for a faster

    acidification of that media, thus avoiding

    contamination during fermentation

    during fermentation undertaken with

    species that grow slowly such as common

    probiotic.

    Why goat’s milk ?

  • Aim

    This work was undertaken to study the

    survival of acid adapted and Non adapted E. coli

    strains in the goat’s milk fermented with starter

    cultures and probiotic bacteria.

  • Raw goat’s milk

    Addition of Skim milk (3%)

    and Gelatine (0.5%)

    Pasteurization

    DEPENDENT VARIABLES

    Viability on

    selective agar

    Inoculation with L. plantarum

    (B411) and starter culture ( L.

    bulgaricus and S. thermophilus)

    Fermentation at 300C for 6 hours

    Fermented goat’s milkAnalyses at 2h interval

    Microbial

    growth/counts

    pH (pH meter)

    TTA

    Environmental E. coli strains

    Induction of acid

    resistance in TS broth at

    pH 4.5

    Inoculation with acid adapted and

    Non-adapted E. coli strains when

    the pH is at 4.5

    Incubation at 370C for

    18h

    Acid adapted E. coli

    strains

    Centrifugation

    Methodology

    Analyses

    Acid Adaptation procedure

  • 4

    5

    6

    7

    8

    9

    10

    Log

    10

    cou

    nts

    (cf

    u/m

    l)

    Growth at pH 4.5

    Growth at pH 7.4

    Survival of environmental E .coli in TS Broth at pH 4.5

    Results

  • CHANGES IN THE PH DURING THE FERMENTATION OF GOAT’S MILK

    4

    4.2

    4.4

    4.6

    4.8

    5

    5.2

    5.4

    5.6

    5.8

    6

    6.2

    0 2 4 6

    pH

    Time (hours)

    starter + Probiotic + NA E.coli probiotic + AA E. coli

    starter + AA E.coli starter + NA E.coli

    starter + Probiotic + AA E.coli Probiotic + NA E. coli

  • 0.1

    0.3

    0.5

    0.7

    0.9

    1.1

    0 2 4 6

    TT

    A

    Time (hours)

    SPNA

    PAA

    SAA

    SNA

    SPAA

    PNA

    CHANGES IN THE TITRATABLE ACIDITY DURING THE FERMENTATION OF GOAT’S MILK.

  • 7.5

    8

    8.5

    9

    9.5

    0 2 4 6L

    og

    10

    cou

    nts

    (cf

    u/m

    l)

    Time (hours)

    Non acid adapted

    7.5

    8

    8.5

    9

    9.5

    0 2 4 6

    Log

    10

    cou

    nts

    (cf

    u/m

    l)

    Time (hours)

    Acid adapted

    starter + probiotic starter Probiotic

    GROWTH OF STARTER CULTURES AND L. PLANTARUM (B411) DURING THE FERMENTATION OF GOAT’S MILK

  • 4

    4.5

    5

    5.5

    6

    6.5

    7

    7.5

    0 2 4 6

    log

    10

    cou

    nts

    (cfu

    /ml)

    Time (hours)

    Non acid adapted

    starter starter + probiotic Probiotic

    4

    4.5

    5

    5.5

    6

    6.5

    7

    7.5

    0 2 4 6

    log

    10

    cou

    nts

    (cfu

    /ml)

    Time (hours)

    Acid adapted

    SURVIVAL OF ACID ADAPTED (AA) AND NON ADAPTED E COLI DURING THE FERMENTATION OF GOAT’S MILK

  • The preliminary results from this study indicate that:

    • Fermentation of the goat’s milk with a single

    strain of L. plantarum does not ensure the safety of the

    product as it allows the survival of both acid adapted and

    non-adapted toxigenic E. coli strains;

    • Inhibition of acid adapted E. coli strains can be

    achieved in fermented goat’s milk through fermentation

    of the product with the combination of starter cultures

    (L. bulgaricus and S. thermophilus) and L. plantarum;

    Conclusions

  • Thank you for

    listening

    The effect of probiotic bacteria on environmental E. coli strains in fermented goat’s milk by FAYEMI, OLANREWAJU EMMANUEL

    (Ph.D) is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

    http://creativecommons.org/licenses/by-nc/4.0/http://creativecommons.org/licenses/by-nc/4.0/http://creativecommons.org/licenses/by-nc/4.0/
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Presented By FAYEMI, OLANREWAJU EMMANUEL (Ph.D) at South African Society of Dairy Technology 46 th Annual General Meeting and Symposium on Food Safety and Security: A dairy perspective. (16th – 19th April, 2013), Khaya Ibhubesi, Parys Free State, South Africa The effect of probiotic bacteria on environmental E. coli strains in fermented goat’s milk by FAYEMI, OLANREWAJU EMMANUEL (Ph.D) is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
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