Emeryserrano8957

t.Humans are mostly contaminated by Salmonella through the consumption of pork- and poultry-derived food products. Therefore, a strict monitoring of Salmonella serotypes in food-producing animals is needed to limit the transmission of the pathogen to humans. Additionally, Salmonella can lead to economic loss in the food sector. Previously, a genoserotyping method using the MOL-PCR and Luminex technology was developed for the identification of the 6 Salmonella serotypes, and their variants, subjected to an official control in the Belgian food sector. In this study, 3 additional assays using the same technology were developed for the rapid and cost-effective detection of 13 dangerous highly invasive serotypes or other serotypes frequently isolated from the Belgian poultry and pork sector, i.e. Agona, Anatum, Brandenburg, Choleraesuis, Derby, Enteritidis vaccine strains, Gallinarum var. Gallinarum/Pullorum, Livingstone, Mbandaka, Minnesota, Ohio, Rissen and Senftenberg. Moreover, the previously developed first MOL-PCR assay was improved for S. Paratyphi B and serogroup O3 detection. Finally, a Decision Support System hosted by a web application was created for an automatic and objective interpretation of the Luminex raw data. The 3 new assays and the modifications of the first assay were validated with a 100% accuracy, using 553 Salmonella and non-Salmonella strains in total.Degradation of undesirable biogenic amines (BAs) in foodstuffs by microorganisms is considered one of the most effective ways of eliminating their toxicity. In this study, we designed two sets of primers for the detection and quantification of the multicopper oxidase gene (MCO), which encodes an enzyme involved in BAs degradation, and endogenous (glyceraldehyde-3-phosphate dehydrogenase) gene (GAPDH) in Lactobacillus casei group by real-time PCR (qPCR). We tested 15 Lactobacillus strains in the screening assays (thus, MCO gene possessing assay (PCR) and monitoring of BAs degradation by HPLC-UV), in which Lactobacillus casei CCDM 198 exhibited the best degradation abilities. For this strain, we monitored the expression of the target gene (MCO) in time (qPCR), the effect of redox treatments (cysteine, ascorbic acid) on the expression of the gene, and the ability to degrade BAs not only in a modified MRS medium (MRS/2) but also in a real food sample (milk). Moreover, decarboxylase activity (ability to form BAs) of this strain was excluded. According to the results, CCDM 198 significantly (P less then 0.05) reduced BAs (putrescine, histamine, tyramine, cadaverine), up to 25% decline in 48 h. The highest level of relative expression of MCO (5.21 ± 0.14) was achieved in MRS/2 media with cysteine.The objective of this study was to explore the correlation between bacterial communities and volatile compounds in traditional dry sausages from different regions in Northeast China. The bacterial community structure of dry sausages from five different regions as determined by high-throughput sequencing technology demonstrated that Firmicutes and Proteobacteria were the predominant phyla; Lactobacillus, Staphylococcus, Leuconostoc, Lactococcus and Weissella were the predominant genera; and Staphylococcus xylosus, Lactobacillus sakei, Weissella hellenica, Leuconostoc citreum, Lactococcus raffinolactis and Lactobacillus plantarum were the predominant species. Meanwhile, a total of 120 volatile compounds were detected in sausages from five different regions and mainly included alcohols, acids, aldehydes, ketones, esters and terpenes. Furthermore, the potential correlations between the core bacteria and major volatile compounds (64) were explored based on Spearman's correlation analysis. Positive correlations were found between W. hellenica, Lb. sakei, Lactococcus lactis, Lactobacillus alimentarius, Lb. plantarum and carboxylic acids and alcohols. Lc. lactis, Lb. alimentarius and Lb. plantarum were associated with the production of most esters, aldehydes and ketones. This study provides a deep insight into the relationship between the bacterial community and the volatile flavour profile of dry sausages, which may be helpful for the production of fermented dry sausages.Due to rapidly falling costs, whole genome sequencing (WGS) is becoming an essential tool in the surveillance of antimicrobial resistance (AMR) in Salmonella enterica. Although there have been many recent works evaluating the accuracy of WGS in predicting AMR from a large number of Salmonella isolates, little attention has been devoted to deciphering the underlying causes of disagreement between the WGS genotype and experimentally determined AMR phenotype. This study analyzed the genomes of six S. enterica isolates previously obtained from raw chicken which exhibited disagreements between WGS genotype and AMR phenotype. A total of five WGS false negative predictions toward ampicillin, amoxicillin/clavulanate, colistin, and fosfomycin resistance were presented in conjunction with their corresponding empirical phenotypic and/or genetic evidence of heteroresistance. A further case study highlighting the inherent limitations of WGS to detect the underlying genetic mechanisms of colistin heteroresistance was presented. These findings implicate heteroresistance as an underlying cause for false negative WGS-based AMR predictions in S. enterica and suggest that widespread use of WGS in the surveillance of AMR in food isolates might severely underestimate true resistance rates.Suancai is a popular fermented product of Brassica vegetable in China. As important additive, salt concentration has crucial effects on the quality of suancai. To investigate the effects of salt concentration on suancai fermentation, the microbial diversity and volatile compounds (VCs) during fermentation were investigated by using Illumina HiSeq sequencing and GC-MS. Firmicutes, Proteobacteria and Ascomycota were detected as the main phylum during the fermentation with different salt concentrations. Lactobacillus, Lactococcus, Klebsiella, Weissella, Pediococcus, Candida, Cladosporium, Gibberella, Aspergillus, etc., were detected were observed during the fermentation with different concentrations. After fermentation, Lactobacillus predominated the fermentation of suancai and was not affected by salt concentration. Pediococcus, Leuconostoc, Weissella, Sporobolomyces, Azospirillum, Klebsiella, Acinetobacter and Cladosporium were significant affected by salt concentration. Salt addition could affect the VCs profiles and reduce the isothiocyanates after fermentation. Seventy-nine VCs were detected and strongly correlated with the dominant genus Lactobacillus during suancai fermentation. The inoculated fermentation of Lactobacillus could improve the VCs during fermentation. In conclusion, 6% salt addition could acquire a higher Lactobacillus abundance and a better taste quality. These results may facilitate the understanding of the effect of salt concentration on the fermentation ecology to improve suancai characteristics.Some beverage-spoiling lactic acid bacteria (LAB) produce capsular β-glucans from UDP-glucose, which is accompanied by cell network formation causing viscosity increases of liquids. This feature of certain LAB is feared in breweries but could be useful for structural and nutritional improvement of baked goods, provided that these LAB are suited for the manufacture of sourdoughs. The aim of this study was to investigate the persistence and β-glucan formation of the brewery isolates Levilactobacillus (L.) brevis TMW 1.2112 and Pediococcus (P.) claussenii TMW 2.340 in wheat and rye sourdoughs. Both the wild-type strains and the respective β-glucan-deficient mutants were dominant in wheat and rye sourdoughs and acidified them to characteristic pH ranges. The formation of β-glucan capsules during sourdough fermentations was stable in L. brevis TMW 1.2112 in contrast to P. claussenii TMW 2.340. Wheat sourdoughs fermented with the β-glucan producing L. brevis TMW 1.2112 cells were significantly more viscous than doughs fermented by the P. claussenii TMW 2.340 cells and the applied mutant strains. In conclusion, L. brevis TMW 1.2112 and P. claussenii TMW 2.340 were suited and persistent wheat and rye sourdough starters, while the in situ β-glucan formation in sourdoughs was hardly detectable in case of P. claussenii.The fate of Listeria monocytogenes during ripening of artisanal Minas semi-hard cheese, as influenced by cheese intrinsic properties and by autochthonous (naturally present) or intentionally-added anti-listerial lactic acid bacteria (LAB) was modeled. Selected LAB strains with anti-listerial capacity were added or not to raw or pasteurized milk to prepare 4 cheese treatments. Counts of LAB and L. monocytogenes, pH, temperature and water activity were determined throughout cheese ripening (22 days, 22±1ᵒC). Different approaches were adopted to model the effect of LAB on L. monocytogenes an independent approach using the Huang primary model to describe LAB growth and the linear decay model to describe pathogen inactivation; the Huang-Cardinal [pH] model using the effect of pH variation in a dynamic tertiary approach; and the Jameson-effect with Nmax tot model which simultaneously describes L. monocytogenes and LAB fate. L. monocytogenes inactivation occurred in both treatments with added LAB and inactivation wa and death. This study presents crucial kinetic data on L. monocytogenes behavior in the presence of competing microbiota in Minas semi-hard cheese under dynamic conditions.Alcoholic fermentation (AF) and malolactic fermentation (MLF) both have significant influence on the production of black raspberry wine. In this study, three microbes associated with AF and MLF including S. cerevisiae, T. delbrueckii and O. oeni were used to investigate their combined effect on basic compositional, volatile and sensory property of black raspberry wine, and four fermentation trials including single S. cerevisiae inoculation plus spontaneous MLF (BSU) and controlled MLF with O. oeni (BSO), sequential culture of T. delbrueckii and S. cerevisiae plus spontaneous MLF (BTSU) and controlled MLF (BTSO) were tested and compared. Fermentation results showed MLF in BSU, BSO and BTSO were successful, with respective period of 40, 25 and 23 days, whereas a stuck MLF occurred in BTSU. Volatile compounds were determined by HS-GC-IMS method, with a total of 45 aromas identified. BTSO was distinguished by a significant higher signal intensity of many fruity esters and a lower production of several alcohols and terpenes, which was in agreement with its perception result of strong 'fruity' and slight note of 'solvent' and 'herbaceous' during quantitative descriptive analysis. On the contrary, BSU was found to reinforce the synthesis of most detected volatiles, resulting in the enhancement of both beneficial and off-flavour compounds, therefore scoring lower in the 'global aroma' descriptor. Principal component analysis showed BSU and BSO were similar in the volatile composition, whereas BTSO was quite different. Overall, BTSO had greater potential to be used in the production of black raspberry wine.In this study, the microbiota of ready-to-eat surströmming from three Swedish producers were studied using a combined approach. The pH values of the samples ranged between 6.67 ± 0.01 and 6.98 ± 0.01, whereas their aw values were between 0.911 ± 0.001 and 0.940 ± 0.001. The acetic acid concentration was between 0.289 ± 0.009 g/100 g and 0.556 ± 0.036 g/100 g. Very low concentrations of lactic acid were measured. Viable counting revealed the presence of mesophilic aerobes, mesophilic lactobacilli and lactococci as well as halophilic lactobacilli and lactococci, coagulase-negative staphylococci, halophilic aerobes and anaerobes. Negligible counts for Enterobacteriaceae, Pseudomonadaceae and total eumycetes were observed, whereas no sulfite-reducing anaerobes were detected. Listeria monocytogenes and Salmonella spp. were absent in all samples. Multiplex real-time PCR revealed the absence of the bont/A, bont/B, bont/E, bont/F, and 4gyrB (CP) genes, which encode botulinic toxins, in all the samples analyzed. Metagenomic sequencing revealed the presence of a core microbiota dominated by Halanaerobium praevalens, Alkalibacterium gilvum, Carnobacterium spp.