Tracking of Intentionally Inoculated Lactic Acid Bacteria Strains in Yogurt and Probiotic Powder

Abstract

The present work aimed at tracking intentionally inoculated lactic acid bacteria (LAB) strains in yogurt and probiotic powder. Leuconostoc (Leu.) mesenteroides (11251), Lactobacillus (L.) brevis (B151), and Lactobacillus plantarum (LB41K) strains were tracked in yogurt, and L. plantarum (LB41P) was tracked in a commercial probiotic powder. The yogurt was intentionally inoculated with the selected bacterial strains. Two types of yogurt with known and unknown bacterial pools were utilized. The standard 16S rRNA gene sequencing was used to evaluate the initial screening. The molecular typing tools, random amplified polymorphic DNA (RAPD), repetitive element palindromic PCR (rep-PCR), and comparative gene sequence analysis of selected housekeeping loci were used to track the inoculated dubious strains. Out of 30 random selections for each inoculation, the developed method identified seven (11251), nine (B151), and five (LB41K) colonies in the yogurt. The validation was performed by identifying 7 colonies (LB41P) out of 30 in the probiotic powder. The DNA banding profiles and the gene sequence alignments led to the identification of the correct inoculated strains. Overall, the study summarizes the use of molecular tools to identify the deliberately inoculated LAB strains. In conclusion, the proposed polyphasic approach effectively tracked the intentionally inoculated strains: Leu. mesenteroides, L. brevis, and L. plantarum (LB41K) in yogurt and L. plantarum (LB41P) in probiotic powder. The study demonstrates how to track industrially relevant misused LAB strains in marketable food products.

Evaluation of randomly amplified polymorphic DNA-polymerase chain reaction method for the identification of eighteen lyophilized probiotics commercially available

“…1C). These results are consistent with previous reports which showed differences or similarities among interspecies through RAPD-PCR analysis (Jarocki et al, 2020;Sharma et al, 2020).…”

“…The principle of RAPD-PCR is that oligonucleotide primers bind to different loci in the genome of a bacterium and randomly amplify unique fragments (Williams et al, 1990). This method is used to reveal the overall differences or similarities among interspecies or intraspecies (Jarocki et al, 2020;Sharma et al, 2020).…”

Development of a High-Resolution Single-Nucleotide Polymorphism Strain-Typing Assay Using Whole Genome-Based Analyses for the Lactobacillus acidophilus Probiotic Strain

“…Sharma et al [ 70 ] successfully used RAPD, a repetitive element–based PCR method, and MLST for tracking intentionally inoculated LAB strains in yogurt and probiotic powder; their proposed polyphasic approach effectively tracked the starter strains. However, such an approach is time- and cost-intensive.…”

Molecular typing tools for identifying and characterizing lactic acid bacteria: a review

“…The wide range and number of applications of LAB make it necessary to associate genomic proof with their important features to exploit their metabolic applications (Stefanovic et al, 2017 ; Wu et al, 2017 ) and identify novel microorganisms at all taxonomic levels rapidly and precisely (Jarocki et al, 2016 ). Furthermore, there is a need for new starter species from the wild LAB pool for generating diverse food and pharmaceutical products that target human health (Sharma et al, 2020 ).…”

“…brevis , and Lb. plantarum from deliberately inoculated yogurt and a commercial probiotic powder (Sharma et al, 2016 ; Sharma et al, 2020 ). Additionally, Lb.…”