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Combination of competitive PCR and cultivation methods for differential enumeration of viable Lactobacillus acidophilus in bio‐yoghurts
Author(s) -
Shakeri MonirSadat,
Shahidi Fakhri,
Mortazavi Ali,
Bahrami Ahmad Reza,
Nassiri Mohammad Reza
Publication year - 2018
Publication title -
international journal of dairy technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.061
H-Index - 53
eISSN - 1471-0307
pISSN - 1364-727X
DOI - 10.1111/1471-0307.12536
Subject(s) - lactobacillus acidophilus , enumeration , food science , bacteria , agar , chemistry , microbiology and biotechnology , biology , probiotic , mathematics , genetics , combinatorics
To ensure the presence of viable Lactobacillus acidophilus in bio‐yoghurts, competitive PCR ( cPCR ) method was optimised using certain amounts of the recombinant plasmid as a non‐homologous competitor. Results showed that this method was well‐suited to detect and identify approximately 1.3 × 10 4 cfu/mL of L. acidophilus bacteria. The developed cPCR method was comparable to the cultivation method with a limit of quantification of approximately 10 4 cfu/g L. acidophilus bacteria. However, the use of MRS ‐bile agar medium alone was not enough for an accurate enumeration of viable L. acidophilus bacteria in commercial bio‐yoghurts. We concluded that the combined assay can be used as a more reliable and cost‐effective alternative for the quality assurance of acidophilus yoghurts.