Behavior of Escherichia coli O157: H7 and Listeria monocytogenes during fermentation and storage of camel yogurt

Anas A. Al-Nabulsi, Amin N. Olaimat, Tareq M. Osaili, Mutamed M. Ayyash, Aisha Abushelaibi, Ziad W. Jaradat, Reyad Shaker, Mahmoud Al-Taani, Richard A. Holley

    Research output: Contribution to journalArticlepeer-review

    16 Citations (Scopus)

    Abstract

    In addition to its nutritional and therapeutic properties, camel milk has the ability to suppress the growth of a wide range of foodborne pathogens, but there is a lack of information regarding the behavior of these pathogens in products such as yogurt produced from camel milk. The objective of the current study was to investigate the behavior of Listeria monocytogenes and Escherichia coli O157:H7 during manufacture and storage of camel yogurt. Camel milk inoculated with L. monocytogenes and E. coli O157:H7 was fermented at 43°C for 5 h using freeze-dried lactic acid bacteria (LAB) starter cultures (Streptococcus thermophilus and Lactobacillus bulgaricus) and stored at 4 or 10°C for 14 d. Camel milk inoculated with L. monocytogenes and E. coli O157:H7 without starter culture was also prepared. During fermentation, the numbers of L. monocytogenes and E. coli O157:H7 increased 0.3 and 1.6 log cfu/mL, respectively, in the presence of LAB, and by 0.3 and 2.7 log cfu/mL in the absence of LAB. During storage at 4 or 10°C, L. monocytogenes increased 0.8 to 1.2 log cfu/mL by 14 d in camel milk without LAB, but in the presence of LAB, the numbers of L. monocytogenes were reduced by 1.2 to 1.7 log cfu/mL by 14 d. Further, E. coli O157:H7 numbers in camel milk were reduced by 3.4 to 3.5 log cfu/mL in the absence of LAB, but E. coli O157:H7 was not detected (6.3 log cfu/mL reduction) by 7 d in camel yogurt made with LAB and stored at either temperature. Although camel milk contains high concentrations of natural antimicrobials, L. monocytogenes was able to tolerate these compounds in camel yogurt stored at refrigerator temperatures. Therefore, appropriate care should be taken during production of yogurt from camel milk to minimize the potential for postprocess contamination by this and other foodborne pathogens.

    Original languageEnglish
    Pages (from-to)1802-1811
    Number of pages10
    JournalJournal of Dairy Science
    Volume99
    Issue number3
    DOIs
    Publication statusPublished - Mar 1 2016

    Keywords

    • Camel milk
    • Escherichia coli O157:H7
    • Lactic acid bacteria
    • Listeria monocytogenes
    • Yogurt

    ASJC Scopus subject areas

    • Food Science
    • Animal Science and Zoology
    • Genetics

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