Rapid porcine detection in gelatin-based highly processed products using loop mediated isothermal amplification.

Low DNA concentration recovered from highly processed products such as gelatin and gelatin-based products renders difficulty in detecting porcine contamination using conventional PCR techniques. We documented here a porcine-specific loop-mediated isothermal amplification (LAMP) to identify porcine traces in gelatin products. The porcine-specific primers were designed according to mitochondrial DNA of Cytochrome b gene sequence. Here we used two different reaction mixtures for LAMP assay (GENIE and MYRM) against the same DNA samples extracted from gelatin products and porcine-specific primers to detect the presence of porcine DNA. The porcine-specific primers were shown to be specific only to Sus scrofa against 14 DNA of other meat species. The analytical sensitivity of the LAMP assay for porcine DNA detection is 1 pg/µL using both GENIE (within 30 m) and MYRM (within 60 m) reaction mixtures. Analysis against 32 samples of gelatin products showed that five samples were found to contain porcine DNA; two samples out of six gelatin powder samples and three gelatin capsule samples out of nine. Out of these five positive samples, three were not labeled containing porcine gelatin. Overall, LAMP assay in this study showed an excellent specificity, sensitivity and rapidity in detection of porcine DNA in gelatin products. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at (10.1007/s13197-020-04932-2).

The Challenges of DNA Extraction in Different Assorted Food Matrices: A Review.

High-quality DNA extracts are imperative for downstream applications in molecular identification. Most processed food products undergo heat treatments causing DNA degradation, which hampers application of DNA-based techniques for food authentication. Moreover, the presence of inhibitors in processed food products is also problematic, as inhibitors can impede the process of obtaining high qualities and quantities of DNA. Various approaches in DNA extraction and factors in structure and texture of various food matrices affecting DNA extraction are explained in this review.

Characterization and antimicrobial activities of two Streptomyces isolates from soil in the periphery of Universiti Putra Malaysia.

This study was to assess the identification and antimicrobial activities of two actinomycete isolates. The two isolates designated as B8 and C2, were isolated from a patch of soil in the peripheral area of Universiti Putra Malaysia by streaking on starch casein agar after standard serial dilution procedures. Their antimicrobial activities were first evaluated against eight clinical laboratory strains namely Bacillus sp., Enterococcus sp., Escherichia coli, Klebsiella sp., Pseudomonas sp., Salmonella sp., Staphylococcus aureus, and Staphylococcus epidermidis by perpendicular streak method on Mueller Hinton and Tryptic Soy agar. In both media, a broad-spectrum antibacterial activity was observed for both isolates, with B8 against all the test bacteria and C2 against five of them (Bacillus sp., E. coli, Pseudomonas sp., S. aureus and S. epidermidis). Re-assessment against E. coli ATCC 25922 and S. aureus ATCC 25923 strains by similar method showed antibacterial activities by isolate B8 against both ATTC strains while C2 only against S. aureus ATCC 25923. Streptomyces griseus ATCC 10137 was included in the later experiment and showed antibacterial activity against both ATCC strains. Subsequently, the two isolates were identified by PCR/sequencing techniques and phylogenetic analysis to be Streptomyces species (>93% homology based on 16S rRNA and rpoB genes). Characterization on cultural characteristic and viable count at different temperatures (37ºC and 28ºC), on different microbiological media (AIA, ISP-2, MHA, NA, PDA and TSA), were performed. More morphological features were observed on ISP-2 for both isolates. A higher growth yield was also observed at 28ºC in all media but in comparing that between the two isolates, isolate B8 outnumbered C2 at all experimental conditions. The observed variation in cultural traits and growth yield indicate unique properties between the two antibiotic-producing isolates.