Detection and identification of tyrDC + enterococcal strains from pasteurized commercial cheeses

Abstract

The aim of this study was to isolate and identify strains of Enterococcus from commercial cheeses and then analyze their abilities to produce biogenic amines. The genotypic variability, studied by randomly amplified polymorphic DNA (RAPD)-PCR, showed a high degree of homogeneity among enterococcal strains. Afterward, genotypic analysis indicated that all strains contain genes encoding a tyrosine decarboxylase. Our results indicate that a potential health risk exists if the enterococcal strains are able to survive the pasteurization of milk or appear as post-pasteurization contaminants. These results highlight the importance of the hazard analysis and critical control point (HACCP) to minimize the risk of hazards associated with post-contamination during cheese elaboration

Safety assessment and functional properties of four enterococci strains isolated from regional Argentinean cheese

“…Remarkably, neither the genetic variability concerning citrate metabolism nor the relationship between citrate fermentation and aroma production have been previously described in E. faecium. In the present study, a comparative genomic analysis of four enterococci strains isolated from Argentinean regional cheeses was performed Suarez et al, 2012). In traditional manufacturing, these naturally occurring strains can pose a threat to human health.…”

Genomic analysis revealed conserved acid tolerance mechanisms from native micro‐organisms in fermented feed

“…Total bacterial genomic DNA was extracted from 2 ml of overnight culture. Bacterial total DNA was obtained as previously performed (Ficarra et al, 2016; Suarez et al, 2012), and yeast total DNA extracted as described by Gardes and Bruns (1993). Total DNA was re‐suspended in 50 µl of TE buffer (Tris‐HCl 10 mmol L −1 , EDTA‐Na 2 1 mmol L −1 , pH 8) and stored at −20℃℃.…”

“…Rod‐shaped micro‐organisms Gram‐positive and catalase‐negative were initially identified by PCR amplification of the 16S rRNA (Ficarra et al, 2016; Suarez et al, 2012). The following primer sets were used, 16S‐341‐Fwd (forward primer 5′‐CCTACGGGAGGCAGCAG‐3′) and 16S‐1389‐Rev (reverse primer 5′‐ACGGGCGGTGTGTACAAG‐3′).…”

“…Total DNA was re-suspended in 50 µl of TE buffer (Tris-HCl 10 mmol L −1 , EDTA-Na 2 1 mmol L −1 , pH 8) and stored at −20℃℃. Random amplified polymorphic DNA (RAPD) analysis was performed using RAPD19 primer (5ʹ-GGTCGACYTTNGYNGGRTC-3ʹ) as previously described by our group (Ficarra et al, 2016;Suarez et al, 2012). Based on the RAPD-PCR profiles, we grouped the isolates to analyse the diversity (Figure S1b).…”

Genome mining of lipolytic exoenzymes from Bacillus safensis S9 and Pseudomonas alcaliphila ED1 isolated from a dairy wastewater lagoon

“…DNA preparation and RAPD reactions were performed as previously described (Suárez et al 2012). Briefly, reactions were carried out in a final volume of 25 μl, using 1 μl of DNA sample as template, 2.5 μmol l −1 of the RAPD19 primer (5′ GGTCGACYTTNGYNGGRTC 3′), 1U of Taq DNA polymerase, 200 μmol l −1 of each dNTP, 1.5 mmol l −1 MgCl 2 in a buffer solution containing 10 mmol l −1 Tris-HCl pH 8, and 50 mmol l −1 KCl.…”