Detection of enterohaemorrhagic Escherichia coli in food by droplet digital PCR to detect simultaneous virulence factors in a single genome.
MG Abstract Shiga toxin producing E. coli are a problem for food producers. STEC's require a combination of virulence factors to cause disease, so ideally detection techniques should detect the presence of multiple virulence factors in a single cell directly from food. Droplet Digital PCR (ddPCR) is commonly used to quantify the number of copies of a gene in a sample, moreover it is able to link two genes to the same piece of DNA. Here stx and an O-antigen specific gene are detected simultaneously with taqman probes confirming that the cells are intact as well as distinguishing between strains based on their geno...
Source: Food Microbiology - April 29, 2020 Category: Food Science Authors: He L, Simpson DJ, Gänzle MG Tags: Food Microbiol Source Type: research

Survival of Salmonella enterica and shifts in the culturable mesophilic aerobic bacterial community as impacted by tomato wash water particulate size and chlorine treatment.
In this study we investigated the survival of Salmonella enterica and the shifts in relative abundance of culturable mesophilic aerobic bacteria (cMAB) as impacted by particulate size and interaction with chlorine treatment. Particulates suspended in grape tomato wash water spanned a wide size range, but the largest contribution came from particles of 3-20 μm. Filtration of wash water through 330 μm, applied after 100 mg/L free chlorine (FC) wash, reduced surviving cMAB by 98%. The combination of filtration (at 330 μm or smaller pore sizes) and chlorinated wash also altered the cMAB community, ...
Source: Food Microbiology - April 29, 2020 Category: Food Science Authors: Van Haute S, Luo Y, Bolten S, Gu G, Nou X, Millner P Tags: Food Microbiol Source Type: research

Novel real-time PCR assay for Lactobacillus casei group species using comparative genomics.
Abstract The Lactobacillus casei group, which includes the closely related species L. casei, L. paracasei, L. rhamnosus, and L. chiayiensis, has been under debate regarding its taxonomy because of the difficulty in distinguishing the species from each other. In the present study, we developed a novel real-time PCR assay for distinguishing the L. casei group species. The pan-genome, as determined by the genomes of 44 strains, comprised 6789 genes, comparative genomic analysis showed that L. casei group strains were classified by species. Based on these results, species-specific genes were identified, and primers we...
Source: Food Microbiology - April 29, 2020 Category: Food Science Authors: Kim E, Yang SM, Cho EJ, Kim HY Tags: Food Microbiol Source Type: research

Correlations between microbiota succession and flavor formation during fermentation of Chinese low-salt fermented common carp (Cyprinus carpio L.) inoculated with mixed starter cultures.
Abstract The correlation between microbiota succession and flavor development in Chinese traditional fermented fish (Suanyu) inoculated with mixed starter cultures was studied. The results showed that 17 free amino acids, 22 free fatty acids and 9 organic acids were present. A total of 81 aroma compounds were detected during Suanyu fermentation. Aldehydes were the most abundant aroma compounds in the early stage of fermentation and esters contributed most to the aroma in the later stage of fermentation. The correlation analysis of microbial succession and flavor dynamics based on bidirectional orthogonal partial l...
Source: Food Microbiology - April 29, 2020 Category: Food Science Authors: Zang J, Xu Y, Xia W, Regenstein JM, Yu D, Yang F, Jiang Q Tags: Food Microbiol Source Type: research

Early adaptation strategies of Saccharomyces cerevisiae and Torulaspora delbrueckii to co-inoculation in high sugar grape must-like media.
This study aimed to compare the cell physiology of the two species, through genome-wide analysis of gene expression, coupling Oxford Nanopore MinION and Illumina Hiseq sequencing platforms. The early transcriptional responses to stress, nutrients and cell-to-cell communication were analysed. Particular attention was given to the fundamental gene modulations, leading to an understanding of the physiological changes needed to maintain cellular homeostasis, exit the quiescent state and establish dominance in the fermentation. Our findings suggest the existence of species-specific adaptation strategies in response to growth in...
Source: Food Microbiology - April 29, 2020 Category: Food Science Authors: Tondini F, Onetto CA, Jiranek V Tags: Food Microbiol Source Type: research

Application of mannitol producing Leuconostoc citreum TR116 to reduce sugar content of barley, oat and wheat malt-based worts.
Abstract Achieving a high monosaccharide composition in malt wort is instrumental to achieve successful lactic acid bacteria fermentation of malt based beverages. The conversion of monosaccharides to alternative metabolites such as the sweet polyol, mannitol with heterofermentative strains presents a novel approach for sugar reduction and to compensate for the loss of sweetness. This work outlines the application of an adopted mashing regimen with the addition of exogenous enzymes to produce wort with high fructose content which can be applied to different malted grain types with consistently efficacious monosacch...
Source: Food Microbiology - April 29, 2020 Category: Food Science Authors: Rice T, Sahin AW, Heitmann M, Lynch KM, Jacob F, Arendt EK, Coffey A Tags: Food Microbiol Source Type: research

Novel insights into the enterotoxigenic potential and genomic background of Staphylococcus aureus isolated from raw milk.
In this study, 53 Staphylococcus (S.) aureus strains were typed by 16S-23S rDNA intergenic spacer region (ISR) typing and staphylococcal enterotoxin gene (SEg) typing for all the staphylococcal enterotoxin (se) and staphylococcal enterotoxin-like toxin (sel) genes known to date, revealing a higher discriminatory power than that of multi locus sequence typing. Six strains, one of each ISR- and SEg-type, were genome sequenced and the ability to produce some classical and new SEs when growing in milk was investigated. The manual analysis of the six genomes allowed us to confirm, correct and expand the results of common availa...
Source: Food Microbiology - April 29, 2020 Category: Food Science Authors: Chieffi D, Fanelli F, Cho GS, Schubert J, Blaiotta G, Franz CMAP, Bania J, Fusco V Tags: Food Microbiol Source Type: research

Heat sensitization of hepatitis A virus and Tulane virus using grape seed extract, gingerol and curcumin.
The objective of this study was to determine and compare the D-values and z-values of HAV and TV at 52-68 °C with or without curcumin (0.015 mg/ml), gingerol (0.1 mg/ml), or GSE (1 mg/ml) in 2-ml glass vials. HAV at ~7 log PFU/ml and TV at ~6 log PFU/ml were diluted in phosphate buffered saline (PBS) and added to two sets of six 2-mL sterile glass vials. One set served as the control and the second set had the three extracts individually added for thermal treatments in a circulating water bath for 0-10 min. The D-values for TV in PBS ranged from 4.55 ± 0.28 to 1.08 ±...
Source: Food Microbiology - April 29, 2020 Category: Food Science Authors: Patwardhan M, Morgan MT, Dia V, D'Souza DH Tags: Food Microbiol Source Type: research

Campylobacter in chicken - Critical parameters for international, multicentre evaluation of air sampling and detection methods.
In conclusion, there was a lack of correspondence between results from analysis of boot swabs and air filters using ISO 10272-1:2017. In contrast, the combination of air filters and direct real-time PCR might be a way forward. Despite the use of the detailed ISO protocols, there were still sections that could be interpreted differently among laboratories. Air sampling may turn into a multi-purpose and low-cost sampling method that may be integrated into self-monitoring programs. PMID: 32336358 [PubMed - in process] (Source: Food Microbiology)
Source: Food Microbiology - April 29, 2020 Category: Food Science Authors: Johannessen GS, Garofolo G, Di Serafino G, Koláčková I, Karpíšková R, Wieczorek K, Osek J, Christensen J, Torp M, Hoorfar J Tags: Food Microbiol Source Type: research

Prevalence of Listeria spp. in produce handling and processing facilities in the Pacific Northwest.
This study investigated the prevalence of Listeria spp. and L. monocytogenes in seven produce handling and processing (PHP) facilities in the Pacific Northwest. PHP facilities were defined as facilities that receive raw agricultural commodities and further handle, pack, wash, or process prior to distribution into the retail sector. Environmental swabs (n = 50/facility) were collected in high-risk areas (e.g., near raw product entry points) from seven PHP facilities over two visits. Listeria spp. were isolated using modified ISO 11290-1 method and speciated with Microgen® Listeria-ID. Listeria spp., including ...
Source: Food Microbiology - April 29, 2020 Category: Food Science Authors: John J, Joy WC, Jovana K Tags: Food Microbiol Source Type: research

A time course metabolism comparison among Saccharomyces cerevisiae, S. uvarum and S. kudriavzevii species in wine fermentation.
In this study, we presented the first metabolome time course analysis performed among a set of S. uvarum, S. kudriavzevii and S. cerevisiae strains under winemaking conditions. Extracellular and intracellular metabolites, as well as physiological parameters of yeast cells, were monitored along the process to find evidence of different metabolic strategies among species to perform alcoholic fermentation. A thorough inspection of time trends revealed several differences in utilization or accumulation of fermentation by-products. We confirmed the ability of S. uvarum and S. kudriavzevii strains to produce higher amounts of gl...
Source: Food Microbiology - April 29, 2020 Category: Food Science Authors: Minebois R, Pérez-Torrado R, Querol A Tags: Food Microbiol Source Type: research

Amino acid and microbial community dynamics during the fermentation of Hong Qu glutinous rice wine.
Abstract Hong Qu glutinous rice wine (HQGRW) is typically very bitter after fermentation due to the presence of bitter amino acids (BAA). The amino acids are considered to primarily derive from the hydrolysis of protein from the raw material by microbial populations during fermentation, and temperature also has an important effect on bitter tastes. Here, the dynamics of fungal and bacterial communities during the traditional fermentation of HQGRW were investigated using high-throughput sequencing and RNA-based rRNA gene sequencing. Both principal component analysis (PCA) and hierarchical clustering analysis (HCA) ...
Source: Food Microbiology - April 29, 2020 Category: Food Science Authors: Liang Z, Lin X, He Z, Su H, Li W, Ren X Tags: Food Microbiol Source Type: research

Selection of non-Lactobacillus strains to be used as starters for sourdough fermentation.
Abstract The suitability of forty-one non-Lactobacillus strains to be used as selected starters for sourdough fermentation was evaluated. According to the data collected, Pediococcus pentosaceus OA1 and S3N3 and Leuconostoc citreum PRO17 were selected based on the optimal acidification and growth performances and the intense proteolytic activity (increase of TFFA up to 80%) on whole wheat flour doughs. A relevant degradation of phytic acid (up to 58%) and the increase of phenols content and scavenging activity (4- and 2-folds, respectively) were also observed. The technological performances were compared to two re...
Source: Food Microbiology - April 29, 2020 Category: Food Science Authors: Montemurro M, Celano G, De Angelis M, Gobbetti M, Rizzello CG, Pontonio E Tags: Food Microbiol Source Type: research

How we can improve the antimicrobial performances of lactic acid bacteria? A new strategy to control Listeria monocytogenes in Gorgonzola cheese.
This study was aimed to evaluate the effectiveness of two lactic acid bacteria (LAB) cultures (Lactococcus lactis FT27 and Carnobacteroim divergens SCA), lactic acid/sodium lactate (LASL - l-lactic acid 61% (w/w) and L-sodium lactate 21% (w/w)) and their combination against four Listeria monocytogenes biotypes isolated from Gorgonzola cheese. In vitro antilisterial activity showed that the sensitivity to antimicrobials was strain-dependent. Antimicrobial challenge testing was performed on Gorgonzola rinds simulating contamination occurring at the beginning (6 days) and at the end (55 days) of the ripening period, to assess...
Source: Food Microbiology - April 29, 2020 Category: Food Science Authors: Morandi S, Silvetti T, Vezzini V, Morozzo E, Brasca M Tags: Food Microbiol Source Type: research

Amino acids other than glutamate affect the expression of the GAD system in Listeria monocytogenes enhancing acid resistance.
Abstract The Glutamate Decarboxylase (GAD) system is important for survival of L. monocytogenes and other microorganisms under acidic conditions. Environmental conditions influence the function of the GAD system. Until now, the only conditions known to lead to increased transcription of the GAD system are the stationary phase in rich media and anoxic conditions. Previously, we showed that transcription of the GAD system requires unidentified compounds other than glutamate present in rich media. Following a test looking at various compounds we identified for first time that peptone, tryptone and casamino acids acti...
Source: Food Microbiology - April 29, 2020 Category: Food Science Authors: Paudyal R, O'Byrne CP, Karatzas KA Tags: Food Microbiol Source Type: research

Efficient isolation of Campylobacter bacteriophages from chicken skin, analysis of several isolation protocols.
M, Lasagabaster A Abstract The application of Campylobacter specific bacteriophages appears as a promising food safety tool for the biocontrol of this pathogen in the poultry meat production chain. However, their isolation is a complicated challenge since their occurrence appears to be low. This work assessed the efficiency of seven protocols for recovering Campylobacter phages from chicken skin samples inoculated at phage loads from 5.0 × 101 to 5.0 × 106 PFU/g. The enrichment of chicken skin in selective Bolton broth containing target isolates was the most efficient procedure...
Source: Food Microbiology - April 29, 2020 Category: Food Science Authors: Nafarrate I, Mateo E, Amárita F, de Marañón IM, Lasagabaster A Tags: Food Microbiol Source Type: research

A loop-mediated isothermal amplification (LAMP) assay for rapid detection of fumonisin producing Aspergillus species.
In this study, we developed a LAMP assay, based on the detection of fum10, for a rapid and specific molecular detection of FB2-producing A. niger and A. welwistchiae, potentially useful to perform monitoring directly "on site" in maize chain. Results showed that very low amounts of conidia are suitable to detect the presence of the target gene, thus providing information about the presence of FB2-producing Aspergillus species and the possible upcoming fumonisins contamination in maize. The assay was combined with a suitable protocol for "in field" crude DNA extraction and a colorimetric method for easy ...
Source: Food Microbiology - April 29, 2020 Category: Food Science Authors: Ferrara M, Logrieco AF, Moretti A, Susca A Tags: Food Microbiol Source Type: research

Tracing Listeria monocytogenes contamination in artisanal cheese to the processing environments in cheese producers in southern Chile.
no-Switt AI Abstract Artisanal cheese from southern Chile is made primarily by rural families who raise dairy cows and produce cheese as a way to add value to their milk. The most common cheese produced is chanco, a semi-hard cheese that is typically sold in unauthorized markets. The methods of chanco production do not always follow good manufacturing practices; however, the presence of Listeria monocytogenes contamination in this cheese has not been previously documented. To better understand production practices and L. monocytogenes contamination, 39 cheese producers were surveyed with regard to infrastructure, ...
Source: Food Microbiology - April 29, 2020 Category: Food Science Authors: Barría C, Singer RS, Bueno I, Estrada E, Rivera D, Ulloa S, Fernández J, Mardones FO, Moreno-Switt AI Tags: Food Microbiol Source Type: research

Increased thermal sensitivity of Listeria monocytogenes in sous-vide salmon by oregano essential oil and citric acid.
In this study, thermal inactivation of L. monocytogenes in sous-vide processed salmon was investigated. Oregano oil and citric acid were used alone or in combination to determine the probability of increasing the efficiency of heat treatment. Control (C); 0.5% citric acid added (S); 1% oregano essential oil added (O); and citric acid and oregano essential oil combined (OS) groups were prepared. Samples were inoculated with L. monocytogenes, vacuum packed, then sous-vide cooked at 55, 57.5, 60, or 62.5 °C for predetermined times. The D-values of all treated samples were significantly lower than control. The use of ...
Source: Food Microbiology - April 29, 2020 Category: Food Science Authors: Dogruyol H, Mol S, Cosansu S Tags: Food Microbiol Source Type: research

Exploring core functional microbiota related with flavor compounds involved in the fermentation of a natural fermented plain sufu (Chinese fermented soybean curd).
This study aimed to explore the core functional microbiotas related to flavor compounds involving in a naturally fermented soybean curd (plain sufu). Properties such as physicochemical parameters, flavor compounds (17 free amino acids, 21 fatty acids, and 14 aroma volatiles) and microbiota profiles were investigated, and their correlations were explored at 8 stages during production. Results from principal component analysis, multiple factor analysis, and partial least squares-discrimination analysis showed that these properties varied significantly in the eight stages. Furthermore, based on Pearson correlation coefficient...
Source: Food Microbiology - April 29, 2020 Category: Food Science Authors: He W, Chung HY Tags: Food Microbiol Source Type: research

Efficacy of sodium hypochlorite and peracetic acid against Aspergillus nomius in Brazil nuts.
The objective of this work was to assess the efficacy of sodium hypochlorite and peracetic acid for sanitization of Brazil nuts. To evaluate the natural microbiota of the nuts, the total bacteria and fungi as well as the Aspergillus section Flavi were counted. The moisture, water activity and the presence of aflatoxins was quantified. The response surface method was used to determine the influence of exposure time and sanitizers concentration on the reduction of Aspergillus nomius inoculated on the nuts. Microbiological, sensory and quantification analyzes of aflatoxins were performed under optimum conditions The evaluatio...
Source: Food Microbiology - April 29, 2020 Category: Food Science Authors: Ribeiro MSS, Freitas-Silva O, Castro IM, Teixeira A, Marques-da-Silva SH, Sales-Moraes ACS, Abreu LF, Sousa CL Tags: Food Microbiol Source Type: research

TMT-based proteomic analysis of the fish-borne spoiler Pseudomonas psychrophila subjected to chitosan oligosaccharides in fish juice system.
Abstract P. psychrophila is implicated in fish spoilage especially under cold storage. In the present study, tandem mass tag (TMT) quantitative proteomic analysis was performed to clarify the molecular mechanism for the inhibitory effect of chitosan oligosaccharides (COS) against P. psychrophila in fish juice system. The MIC and MBC of the COS against P. psychrophila were 6 and 8 mg/mL, respectively. Compared with the untreated control, a total of 370 proteins (163 up-regulated and 207 down-regulated) were identified as differentially expressed proteins (DEPs,>1.5-fold or 
Source: Food Microbiology - April 29, 2020 Category: Food Science Authors: Jia S, Hong H, Yang Q, Liu X, Zhuang S, Li Y, Liu J, Luo Y Tags: Food Microbiol Source Type: research

Bacillus cereus spores and toxins - The potential role of biofilms.
Abstract Bacillus cereus is a well-known foodborne pathogen capable of causing two types of gastrointestinal diseases, diarrhoea and emesis. It is of particular concern for the food industry causing food safety issues, due to the formation of spores, biofilms and diarrhoea and/or emetic toxins. This review reveals the possible link between two food safety issues - toxins and spores - and the role of biofilms. The review highlights genetic determinants that are involved in sporulation, toxin production and biofilm formation based on current research, and evidence showing the possible correlation of spore, toxin and...
Source: Food Microbiology - April 29, 2020 Category: Food Science Authors: Huang Y, Flint SH, Palmer JS Tags: Food Microbiol Source Type: research

Investigating the effects of Aureobasidium pullulans on grape juice composition and fermentation.
In this study, the physiology of abundant A. pullulans grape juice isolates was investigated through lab scale fermentation trials, demonstrating the ability of this species to survive in grape juice while producing polysaccharides, polymers of malic acid (poly β-malic acid) and enzymes with pectinase, β - glucosidase and tannase activity. A possible antagonistic effect against yeast through competition for metals including Fe and Zn was also observed. Overall, the data suggests this abundant species could have important implications for wine production and quality. PMID: 32336373 [PubMed - in process] (Sour...
Source: Food Microbiology - April 29, 2020 Category: Food Science Authors: Onetto CA, Borneman AR, Schmidt SA Tags: Food Microbiol Source Type: research

Transcriptomics unravels the adaptive molecular mechanisms of Brettanomyces bruxellensis under SO2 stress in wine condition.
ini I Abstract Sulfur dioxide is generally used as an antimicrobial in wine to counteract the activity of spoilage yeasts, including Brettanomyces bruxellensis. However, this chemical does not exert the same effectiveness on different B. bruxellensis yeasts since some strains can proliferate in the final product leading to a negative sensory profile due to 4-ethylguaiacol and 4-ethylphenol. Thus, the capability of deciphering the general molecular mechanisms characterizing this yeast species' response in presence of SO2 stress could be considered strategic for a better management of SO2 in winemaking. A RNA-Seq ap...
Source: Food Microbiology - April 29, 2020 Category: Food Science Authors: Valdetara F, Škalič M, Fracassetti D, Louw M, Compagno C, du Toit M, Foschino R, Petrovič U, Divol B, Vigentini I Tags: Food Microbiol Source Type: research

Tolerance to acid and alkali by Streptococcus infantarius subsp. infantarius strain 25124 isolated from fermented nixtamal dough: Pozol. Studies in APT broth.
ay M, Sainz T, Wacher C Abstract Pozol is a beverage prepared with maize dough made after boiling the kernels in limewater. This pretreatment could act as a selective force that shapes the starter microbiota, with microorganisms able to survive the fermentation. Since Streptococcus infantarius subsp. infantarius (Sii) dominates in pozol, we evaluated the effect of acid and alkali stresses on strain Sii-25124 in commercial APT broth as a first attempt to assess its adaptation capacity. Results suggest that Sii-25124 has adaptative advantages to pH changes that possibly contribute to its persistence even after the a...
Source: Food Microbiology - April 29, 2020 Category: Food Science Authors: Domínguez-Ramírez LL, Rodríguez-Sanoja R, Tecante A, García-Garibay M, Sainz T, Wacher C Tags: Food Microbiol Source Type: research

Lactobacillus fermentum: Could EPS production ability be responsible for functional properties?
Abstract Exopolysaccharides (EPS) production is a characteristic that has been widely described for many lactic acid bacteria (LAB) of different genera and species, but little is known about the relationship between the functional properties of the producing bacteria and EPS synthesis. Although many studies were addressed towards the application of EPS-producing LAB in the manufacture of several dairy products (fermented milk, cheese) due to their interesting technological properties (increased hardness, water holding capacity, viscosity, etc.), there are not many reports about the functional properties of the EPS...
Source: Food Microbiology - April 29, 2020 Category: Food Science Authors: Ale EC, Rojas MF, Reinheimer JA, Binetti AG Tags: Food Microbiol Source Type: research

Synergistic antimicrobial activity of oregano and thyme thymol essential oils against Leuconostoc citreum in a laboratory medium and tomato juice.
This study was done to identify combinations of essential oils (EOs) that elicit synergistic antimicrobial effects against Leuconostoc citreum, a spoilage bacterium in vegetable and fruit juices. Twenty-four EOs were tested for antimicrobial activity against L. citreum using an agar well diffusion assay. Ten EOs showed relatively strong antimicrobial activity. Among those, cinnamon bark, oregano, and thyme thymol EOs showed the strongest activity (minimal inhibitory concentration = 1.25 μL/mL). It was confirmed that a combination of oregano and thyme thymol EOs had a synergistic antimicrobial activity (fr...
Source: Food Microbiology - April 29, 2020 Category: Food Science Authors: Lee S, Kim H, Beuchat LR, Kim Y, Ryu JH Tags: Food Microbiol Source Type: research

Study of the microbiological quality, prevalence of foodborne pathogens and product shelf-life of Gilthead sea bream (Sparus aurata) and Sea bass (Dicentrarchus labrax) from aquaculture in estuarine ecosystems of Andalusia (Spain).
This study was aimed at characterizing microbiologically Gilthead sea bream (Sparus aurata) and Sea bass (Dicentrarchus labrax) produced in two estuarine ecosystems in Andalusia (Spain): the estuary of the river Guadalquivir (La Puebla del Río, Sevilla) (A), and the estuary of the river Guadiana (Ayamonte, Huelva) (B). The collected fish individuals and water were analysed for hygiene indicator microorganisms and pathogens. The statistical analysis of results revealed that microbial counts for the different microbiological parameters were not statistically different for fish type. On the contrary, considering anatom...
Source: Food Microbiology - April 29, 2020 Category: Food Science Authors: Correia Peres Costa JC, Floriano B, Bascón Villegas IM, Rodríguez-Ruiz JP, Posada-Izquierdo GD, Zurera G, Pérez-Rodríguez F Tags: Food Microbiol Source Type: research

Effects of initial oxygenation on chemical and aromatic composition of wine in mixed starters of Hanseniaspora vineae and Saccharomyces cerevisiae.
Abstract The use of Saccharomyces and non-Saccharomyces yeast species as mixed starters has potential advantages over pure culture fermentation due to increased wine complexity based on modification of metabolites of oenological interest. In this work, the effects of initial oxygenation on fermentation performance, chemical and volatile composition of French Colombard wine fermented with Hanseniaspora vineae and Saccharomyces cerevisiae in sequential inoculations were investigated in 1 L flasks. Although dominated by S. cerevisiae at the middle-end of fermentation, initial aeration for 1 day boosted H. vineae...
Source: Food Microbiology - April 29, 2020 Category: Food Science Authors: Yan G, Zhang B, Joseph L, Waterhouse AL Tags: Food Microbiol Source Type: research

Comparative genetic and physiological characterisation of Pectinatus species reveals shared tolerance to beer-associated stressors but halotolerance specific to pickle-associated strains.
Abstract Obligate anaerobic bacteria from the genus Pectinatus have been known to cause beer spoilage for over 40 years. Whole genome sequencing was performed on eleven beer spoilage strains (nine Pectinatus frisingensis, one Pectinatus cerevisiiphilus and one Pectinatus haikarae isolate), as well as two pickle spoilage species (Pectinatus brassicae MB591 and Pectinatus sottacetonis MB620) and the tolerance of all species to a range of environmental conditions was tested. Exploration of metabolic pathways for carbohydrates, amino acids and vitamins showed little difference between beer spoilage- and pickle spoilag...
Source: Food Microbiology - April 29, 2020 Category: Food Science Authors: Kramer T, Kelleher P, van der Meer J, O'Sullivan T, Geertman JA, Duncan SH, Flint HJ, Louis P Tags: Food Microbiol Source Type: research

Effect of temperature on the growth of Staphylococcus aureus in ready-to-eat cooked rice with pork floss.
The objective of this study was to examine the effect of temperature on its growth in RTE CRPF for use in risk assessment and prevention of staphylococcal food poisoning (SFP). Inoculated CRPF samples were stored at 4, 12, 18, 25, and 35°C, and the change in the populations of S. aureus during storage were analyzed using three primary models to determine specific growth rate (μmax), lag-phase duration (λ), and maximum population density (ymax). The Ratkowsky square-root and Huang square-root (HSR) models were used as the secondary models to describe the effect of temperature on μmax, and a linear and an ex...
Source: Food Microbiology - March 7, 2020 Category: Food Science Authors: Lu KH, Sheen YJ, Huang TP, Kao SH, Cheng CL, Hwang CA, Sheen S, Huang L, Sheen LY Tags: Food Microbiol Source Type: research

Regulation of trehalose, a typical stress protectant, on central metabolisms, cell growth and division of Saccharomyces cerevisiae CEN.PK113-7D.
Abstract Trehalose could protect the typical food microorganism Saccharomyces cerevisiae cell against environmental stresses; however, the other regulation effects of trehalose on yeast cells during the fermentation are still poorly understood. In this manuscript, different concentrations (i.e., 0, 2 and 5% g/v) of trehalose were respectively added into the medium to evaluate the effect of trehalose on growth, central metabolisms and division of S. cerevisiae CEN.PK113-7D strain that could uptake exogenous trehalose. Results indicated that addition of trehalose could inhibit yeast cell growth in the presence or ab...
Source: Food Microbiology - March 7, 2020 Category: Food Science Authors: Zhang X, Zhang Y, Li H Tags: Food Microbiol Source Type: research

Diversity of the metabolic profiles of a broad range of lactic acid bacteria in soy juice fermentation.
This study explores the ability of lactic acid bacteria (LAB) to ferment soy juice. The ability of 276 LAB strains from 25 species to ferment the principal soy carbohydrates, sucrose, raffinose or stachyose was tested in synthetic media and a soy juice. Fermented soy juices (FSJs) were characterized for their odor. Selected FSJs were characterized by targeted metabolomics. All Streptococcus, 83% of Leuconostoc and Lactobacillus and 41% of Lactococcus strains were sucrose-positive, while only 36% of all the LAB strains tested were raffinose-positive and 6% stachyose-positive. Nearly all (97%) the sucrose-positive strains fe...
Source: Food Microbiology - March 7, 2020 Category: Food Science Authors: Harlé O, Falentin H, Niay J, Valence F, Courselaud C, Chuat V, Maillard MB, Guédon É, Deutsch SM, Thierry A Tags: Food Microbiol Source Type: research

Evaluation of a hybrid in-field sampling method for the detection of pathogenic bacteria through consideration of a priori knowledge of factors related to non-random contamination.
Abstract Pre-harvest testing is increasingly used to enhance the microbial safety of fresh produce. Traditional sampling assumes that sample collectors have no information on potential contamination sources. Knowledge of such factors could potentially increase the effectiveness of pre-harvest sampling programs. Simulation modeling and field validation trials were used to evaluate a hybrid "Samples of Opportunity" (SOO) sampling method that included a portion of the samples based on the sampler's knowledge of risk factors in pre-harvest produce fields. Relative effectiveness of SOO sampling was compared w...
Source: Food Microbiology - March 7, 2020 Category: Food Science Authors: Xu A, Buchanan RL Tags: Food Microbiol Source Type: research

Effect of combination of Oxyrase and sodium thioglycolate on growth of Clostridium perfringens from spores under aerobic incubation.
Abstract Clostridium perfringens is a strictly anaerobic pathogen that requires absence of oxygen for its growth in laboratory experiments, which is usually attained by using an anaerobic chamber or anaerobic jars. However, it has been demonstrated that C. perfringens may survive for short periods of times due to its adaptive response to O2. Therefore, the objective of this study was to explore the application of Oxyrase (OX) and sodium thioglycolate (ST) as oxygen scavengers, used alone or in combination, for observation of the growth of C. perfringens under aerobic incubation. The growth of C. perfringens from s...
Source: Food Microbiology - March 7, 2020 Category: Food Science Authors: Jia Z, Liu Y, Hwang CA, Huang L Tags: Food Microbiol Source Type: research

Hepatitis E virus genotype 3 in echinoderms: First report of sea urchin (Paracentrotus lividus) contamination.
imento MSJ Abstract Hepatitis E virus (HEV) deriving from manure application runoffs and faecal waste spill over of swine and human origin bypass wastewater treatment plants and contaminate coastal waters. Shellfish bioaccumulate enteric viruses such as HEV from fecally contaminated coastal waters and under current European Regulations, shellfish sanitary status surveillance is mandatory but only by means of bacterial faecal indicators. The sea urchins are under the same regulations and their vulnerability to fecal contamination has been pointed out. Since they are consumed raw and with no steps to control/reduce ...
Source: Food Microbiology - March 7, 2020 Category: Food Science Authors: Santos-Ferreira N, Mesquita JR, Rivadulla E, Inácio ÂS, Martins da Costa P, Romalde JL, Nascimento MSJ Tags: Food Microbiol Source Type: research

Phenotype and genomic background of Arcobacter butzleri strains and taxogenomic assessment of the species.
In this study the phenotypic and genomic characterization of two Arcobacter butzleri (Ab) strains (Ab 34_O and Ab 39_O) isolated from pre-cut ready-to-eat vegetables were performed. Results provided useful data about their taxonomy and their overall virulence potential with particular reference to the antibiotic and heavy metal susceptibility. These features were moreover compared with those of two Ab strains isolated from shellfish and a genotaxonomic assessment of the Ab species was performed. The two Ab isolated from vegetables were confirmed to belong to the Aliarcobacter butzleri species by 16S rRNA gene sequence anal...
Source: Food Microbiology - March 7, 2020 Category: Food Science Authors: Fanelli F, Chieffi D, Di Pinto A, Mottola A, Baruzzi F, Fusco V Tags: Food Microbiol Source Type: research

Characterization of the microbial community composition in Italian Cinta Senese sausages dry-fermented with natural extracts as alternatives to sodium nitrite.
In conclusion, NGS analysis showed that the prokaryotic community composition was similar in GSE and NIT, while CHE varied in both the composition and relative abundance of different taxa. PMID: 32138987 [PubMed - in process] (Source: Food Microbiology)
Source: Food Microbiology - March 7, 2020 Category: Food Science Authors: Pini F, Aquilani C, Giovannetti L, Viti C, Pugliese C Tags: Food Microbiol Source Type: research

Proteomic study of Enterococcus durans LAB18S growing on prebiotic oligosaccharides.
This study evaluates the influence of prebiotic carbohydrates, namely fructooligosaccharides (FOS) and galactooligosaccharides (GOS), on the protein expression of Enterococcus durans LAB18S. The strain was cultivated in 10 g L-1 FOS, GOS or glucose (control) and cellular proteins were extracted for mass spectrometry analysis. A total of 771 proteins were identified and 135 E. durans proteins were validated by the Scaffold algorithm. The proteins were functionally categorized according to Gene Ontology terms. Both FOS and GOS were used as carbon source by E. durans LAB18S, upregulating the production of proteins t...
Source: Food Microbiology - March 7, 2020 Category: Food Science Authors: Comerlato CB, Ritter AC, Miyamoto KN, Brandelli A Tags: Food Microbiol Source Type: research

Effect of endogenous CO2 overpressure on the yeast "stressome" during the "prise de mousse" of sparkling wine.
This study focuses on the stressome evolution along the prise de mousse under CO2 overpressure conditions in an industrial S. cerevisiae strain. The results reveal an important effect of endogenous CO2 overpressure on the stress sub-proteome, cell viability and metabolites such as glycerol, reducing sugars and ethanol. Whereas the content of glycerol biosynthesis-related proteins increased in sealed bottle, those involved in the response to toxic metabolites like ROS, ethanol, acetaldehyde and acetic acid, decreased in content. Proteomic profile obtained in this study may be used to select suitable wine yeast strains for s...
Source: Food Microbiology - March 7, 2020 Category: Food Science Authors: Porras-Agüera JA, Román-Camacho JJ, Moreno-García J, Mauricio JC, Moreno J, García-Martínez T Tags: Food Microbiol Source Type: research

Prevalence and genetic characteristics of Cronobacter spp. from food and human clinical stool samples in Wenzhou, China 2008-2018.
Abstract Pathogenic Cronobacter species are responsible for life-threatening illness in neonates. A ten-year comprehensive survey was conducted to examine the population structure and antimicrobial resistant patterns of Cronobacter isolates from food (n = 78) and clinical (n = 12) sources in Wenzhou, China. A total of 90 (4.4%) isolates were recovered from 2051 collected samples. The occurrence of Cronobacter spp. was highest in spices with a rate of 22% (26/119), whereas the lowest contamination rate of 1% was found in powered infant and toddler formula (7/494), special medical infant formula ...
Source: Food Microbiology - March 7, 2020 Category: Food Science Authors: Li Y, Zhang Y, Zhang L, Hu Y, Hong C, Xie A, Wu Y, Shangguan Z, Zhou B, Fang L, Mei L Tags: Food Microbiol Source Type: research

Attribution of Listeria monocytogenes human infections to food and animal sources in Northern Italy.
Abstract Listeriosis is a foodborne illness characterized by a relatively low morbidity, but a large disease burden due to the severity of clinical manifestations and the high case fatality rate. Increased listeriosis notifications have been observed in Europe since the 2000s. However, the reasons for this increase are largely unknown, with the sources of sporadic human listerioris often remaining elusive. Here we inferred the relative contributions of several putative sources of Listeria monocytogenes strains from listerioris patients in Northern Italy (Piedmont and Lombardy regions), using two established source...
Source: Food Microbiology - March 7, 2020 Category: Food Science Authors: Filipello V, Mughini-Gras L, Gallina S, Vitale N, Mannelli A, Pontello M, Decastelli L, Allard MW, Brown EW, Lomonaco S Tags: Food Microbiol Source Type: research

Raw meat quality and salt levels affect the bacterial species diversity and community dynamics during the fermentation of pork mince.
Abstract Acidification level and temperature modulate the beneficial consortia of lactic acid bacteria (LAB) and coagulase-negative staphylococci (CNS) during meat fermentation. Less is known about the impact of other factors, such as raw meat quality and salting. These could for instance affect the growth of the pathogen Staphylococcus aureus or of Enterobacterales species, potentially indicative of poor fermentation practice. Therefore, pork batters from either normal or borderline quality (dark-firm-dry, DFD) were compared at various salt concentrations (0-4%) in meat fermentation models. Microbial ecology of t...
Source: Food Microbiology - March 7, 2020 Category: Food Science Authors: Charmpi C, Van der Veken D, Van Reckem E, De Vuyst L, Leroy F Tags: Food Microbiol Source Type: research

Addition of volatile sulfur compounds to yeast at the early stages of fermentation reveals distinct biological and chemical pathways for aroma formation.
Abstract Volatile sulfur compounds (VSCs) greatly influence the sensory properties and quality of wine and arise via both biological and chemical mechanisms. VSCs formed can also act as precursors for further downstream VSCs, thus elucidating the pathways leading to their formation is paramount. Short-term additions of exogenous hydrogen sulfide (H2S), ethanethiol (EtSH), S-ethylthio acetate (ETA), methanethiol (MeSH) and S-methylthio acetate (MTA) were made to exponentially growing fermentations of synthetic grape medium. The VSC profiles produced from live yeast cells were compared with those from dead cells and...
Source: Food Microbiology - March 7, 2020 Category: Food Science Authors: Kinzurik MI, Deed RC, Herbst-Johnstone M, Slaghenaufi D, Guzzon R, Gardner RC, Larcher R, Fedrizzi B Tags: Food Microbiol Source Type: research

Volatile organic compounds from Starmerella bacillaris to control gray mold on apples and modulate cider aroma profile.
Abstract Gray mold caused by Botrytis cinerea is a fungal disease that can determine significant economic losses of apple during the storage phase. An alternative to reduce the use of traditional synthetic fungicides is to employ the yeast Starmerella bacillaris as biological control agent (BCA), also with positive effect on apple juice fermentation for the production of cider. Thus, we aimed to evaluate the safety of 16 S. bacillaris strains and their ability to control B. cinerea. In addition, the fermentation performances in apple juice and the volatile organic compounds (VOCs) profile were assessed, both in si...
Source: Food Microbiology - March 7, 2020 Category: Food Science Authors: Lemos Junior WJF, Binati RL, Felis GE, Slaghenaufi D, Ugliano M, Torriani S Tags: Food Microbiol Source Type: research

Comparative evaluation of UNEX-based DNA extraction for molecular detection of Cyclospora cayetanensis, Toxoplasma gondii, and Cryptosporidium parvum as contaminants of berries.
Abstract The potential public health impact of foodborne parasites (FBP) transmitted via contaminated fresh produces indicates the necessity for robust and reliable laboratory methods for their detection and identification on this infection vehicle. Standardization of methods for detection of common FBP in fresh produce is to be expected and ensuring that the DNA extraction approach is most appropriate for the FBP of interest and for the matrix being analyzed is also important. Therefore, the aim of the present study was to compare the efficacy of two commercially available DNA extraction procedures, the UNEX-base...
Source: Food Microbiology - March 7, 2020 Category: Food Science Authors: Temesgen TT, Barlaam A, Tysnes KR, Robertson LJ Tags: Food Microbiol Source Type: research

Comparative genomics of Lactobacillus fermentum suggests a free-living lifestyle of this lactic acid bacterial species.
This study explained the traits that were previously demonstrated for L. fermentum IMDO 130101 at the genetic level and provided future avenues of research regarding L. fermentum strains isolated from sourdough. PMID: 32138996 [PubMed - in process] (Source: Food Microbiology)
Source: Food Microbiology - March 7, 2020 Category: Food Science Authors: Verce M, De Vuyst L, Weckx S Tags: Food Microbiol Source Type: research

Fates of pathogenic bacteria in time-temperature-abused and Holder-pasteurized human donor-, infant formula-, and full cream cow's milk.
This study was conducted to address the dearth in works that simultaneously compare the growth and inactivation behaviors of selected pathogens in different milk products. In worst-case scenarios where hygienic practices are absent and heavy microbiological contaminations occur, Salmonella enterica, Escherichia coli O157:H7, Listeria monocytogenes, Pseudomonas aeruginosa, and Staphylococcus aureus multiplied in all samples at room temperature (27 °C). Most organisms readily proliferated with growth lag (tlag) values ranging from 0.00 to 5.95 h. Growth rates (KG) ranged from 0.16 to 0.67 log CFU/h. Sanitary ri...
Source: Food Microbiology - March 7, 2020 Category: Food Science Authors: Gabriel AA, Bayaga CLT, Magallanes EA, Aba RPM, Tanguilig KMN Tags: Food Microbiol Source Type: research

Evaluation of real-time nanopore sequencing for Salmonella serotype prediction.
This study demonstrated the comparable accuracy of WGS-based serotype prediction between ONT and Illumina sequencing platforms. This study also sets a start point for future validation of ONT WGS as a rapid Salmonella confirmation and serotype classification tool for the food industry. PMID: 32138998 [PubMed - in process] (Source: Food Microbiology)
Source: Food Microbiology - March 7, 2020 Category: Food Science Authors: Xu F, Ge C, Luo H, Li S, Wiedmann M, Deng X, Zhang G, Stevenson A, Baker RC, Tang S Tags: Food Microbiol Source Type: research