Effect of high pressure processing on the survival of Salmonella Enteritidis and shelf-life of chicken fillets.
Abstract High pressure processing (HPP) is a preservation technology alternative to heat treatment that is mild for food, but effectively inactivates the spoilage microbiota and foodborne pathogens of several foods. The purpose of the current study was to evaluate the effect of HPP on Salmonella ser. Enteritidis, indigenous microbiota and shelf-life of chicken fillets. Chicken fillets were inoculated with S. Enteritidis at three different initial inocula (3, 5, 7 log CFU/g), packed under vacuum, treated or not with HPP (500 MPa/10 min) and stored at 4 and 12 °C. Total viable counts, S. Enteritidis, p...
Source: Food Microbiology - November 29, 2017 Category: Food Science Authors: Argyri AA, Papadopoulou OS, Nisiotou A, Tassou CC, Chorianopoulos N Tags: Food Microbiol Source Type: research

Microbial biodiversity of Sardinian oleic ecosystems.
Abstract The olives are rich in microorganisms that, during the extraction process may persist in the oils and can influence their physicochemical and sensory characteristics. In this work, and for the first time, we isolated and identified microbial species, yeast and bacteria, present during the production process in four Sardinian (Italy) oleic ecosystems. Among these varieties, we found that Nera di Gonnos was associated to the highest microbial biodiversity, which was followed by Bosana, Nocellara del Belice and Semidana. Among the different microbial species isolated, some are specific of olive ecological ni...
Source: Food Microbiology - November 29, 2017 Category: Food Science Authors: Santona M, Sanna ML, Multineddu C, Fancello F, de la Fuente SA, Dettori S, Zara S Tags: Food Microbiol Source Type: research

Diversity of bacterial communities in French chicken cuts stored under modified atmosphere packaging.
rec M Abstract Poultry meat, the second most consumed meat in France, is commercialized mainly as portions of chicken cuts with various quality labels, stored under various modified atmosphere packaging (MAP), with shelf-life ranging from 9 to 17 days. We used 16S rDNA pyrosequencing to describe microbiota of chicken legs. Ten samples representing a wide diversity of labels and MAP available on the market were collected from local supermarkets and stored at 4 °C. Microbiota were collected, total DNA was extracted, and V1-V3 fragment of 16S rRNA genes were amplified and sequenced. For data analysis several...
Source: Food Microbiology - November 29, 2017 Category: Food Science Authors: Rouger A, Moriceau N, Prévost H, Remenant B, Zagorec M Tags: Food Microbiol Source Type: research

Primary souring: A novel bacteria-free method for sour beer production.
Abstract In the beverage fermentation industry, especially at the craft or micro level, there is a movement to incorporate as many local ingredients as possible to both capture terroir and stimulate local economies. In the case of craft beer, this has traditionally only encompassed locally sourced barley, hops, and other agricultural adjuncts. The identification and use of novel yeasts in brewing lags behind. We sought to bridge this gap by bio-prospecting for wild yeasts, with a focus on the American Midwest. We isolated 284 different strains from 54 species of yeast and have begun to determine their fermentation...
Source: Food Microbiology - November 29, 2017 Category: Food Science Authors: Osburn K, Amaral J, Metcalf SR, Nickens DM, Rogers CM, Sausen C, Caputo R, Miller J, Li H, Tennessen JM, Bochman ML Tags: Food Microbiol Source Type: research

Seafood pathogens and information on antimicrobial resistance: A review.
Abstract Seafood-borne diseases are a major public health hazard in the United States and worldwide. Per capita, seafood consumption has increased globally during recent decades. Seafood importation and domestic aquaculture farming has also increased. Moreover, several recent outbreaks of human gastroenteritis have been linked to the consumption of contaminated seafood. Investigation of seafood-borne illnesses caused by norovirus, and Vibrio, and other bacteria and viruses require a concrete knowledge about the pathogenicity and virulence properties of the etiologic agents. This review explores pathogens that have...
Source: Food Microbiology - November 29, 2017 Category: Food Science Authors: Elbashir S, Parveen S, Schwarz J, Rippen T, Jahncke M, DePaola A Tags: Food Microbiol Source Type: research

Different Lactobacillus populations dominate in "Chorizo de Le ón" manufacturing performed in different production plants.
In this study, samples from raw minced meat to final products were taken from five different producers and the microbial diversity was investigated by high-throughput sequencing of 16S rRNA gene amplicons. The diverse microbial composition observed during the first stages of "Chorizo de Léon" evolved during ripening to a microbiota mainly composed by Lactobacillus in the final product. Oligotyping performed on 16S rRNA gene sequences of Lactobacillus and Staphylococcus populations revealed sub-genus level diversity within the different manufacturers, likely responsible of the characteristic organoleptic pr...
Source: Food Microbiology - November 29, 2017 Category: Food Science Authors: Quijada NM, De Filippis F, Sanz JJ, García-Fernández MDC, Rodríguez-Lázaro D, Ercolini D, Hernández M Tags: Food Microbiol Source Type: research

Biofilm production by Aureobasidium pullulans improves biocontrol against sour rot in citrus.
Abstract The biocontrol efficiency of Aureobasidium pullulans strain ACBL-77 against Geotrichum citri-aurantii, causal agent of sour rot in citrus, and their interactions were evaluated. For this, were evaluated the incorporation of nutrients in optimizing the antagonistic activity of the yeast, the competition for nutrients between microorganisms, the effect of nutrients on yeast cell and biofilm production and their correlation in the biocontrol of disease, the survival of yeast in citrus fruits and the interaction between microorganisms using scanning electron microscopy. Micronutrients (boric acid, cobalt chlo...
Source: Food Microbiology - September 26, 2017 Category: Food Science Authors: Klein MN, Kupper KC Tags: Food Microbiol Source Type: research

Comparison study of the volatile profiles and microbial communities of Wuyi Qu and Gutian Qu, two major types of traditional fermentation starters of Hong Qu glutinous rice wine.
Abstract Hong Qu, which mainly contains Monascus sp. and other microorganisms, as well as numerous microbial metabolites, is used as the fermentation starter of Hong Qu glutinous rice wine, a traditional alcoholic beverage. Two widely-used types of Hong Qu, namely Wuyi Qu (WYQ) and Gutian Qu (GTQ), were thoroughly compared for their fermentation properties, volatile profiles, and microbiota structures in this study. Significantly higher color value, glucoamylase and α-amylase activities were discovered in WYQ. And substantial variation in volatile components and microbial communities were also observed betwe...
Source: Food Microbiology - September 26, 2017 Category: Food Science Authors: Liu Z, Wang Z, Lv X, Zhu X, Chen L, Ni L Tags: Food Microbiol Source Type: research

Viability of and Escherichia coli O157:H7 and Listeria monocytogenes in a delicatessen appetizer (yogurt-based) salad as affected by citrus extract (Citrox( ©)) and storage temperature.
Viability of and Escherichia coli O157:H7 and Listeria monocytogenes in a delicatessen appetizer (yogurt-based) salad as affected by citrus extract (Citrox(©)) and storage temperature. Food Microbiol. 2018 Feb;69:11-17 Authors: Tsiraki MI, Yehia HM, Elobeid T, Osaili T, Sakkas H, Savvaidis IN Abstract The antimicrobial effect of citrus extract (at 1 mL/kg [C1] and 2 mL/kg [C2]) on naturally occurring microbiota and inoculated pathogens (E. coli O157:H7 and L. monocytogenes at ca. 6 log cfu/g) in the traditional Greek yogurt-based salad Tzatziki stored at 4, 10, or 21 °C, w...
Source: Food Microbiology - September 26, 2017 Category: Food Science Authors: Tsiraki MI, Yehia HM, Elobeid T, Osaili T, Sakkas H, Savvaidis IN Tags: Food Microbiol Source Type: research

Folates biosynthesis by Streptococcus thermophilus during growth in milk.
Abstract The ability of folate-producer strains of Streptococcus thermophilus to accumulate folates and the expression of two target genes (folK and folP), involved in the folate biosynthesis, were studied during milk fermentation. An over-expression of folK took place only in the early phase of growth, whereas folP was mainly expressed in the mid log-phase of growth and declined thereafter. The accumulation of total folates, which was quantified by a microbiological assay, was strain-dependent. Two major forms of folates, i.e. tetrahydrofolate (THF) and 5-methyl-tetrahydrofolate (5-Met-THF), were identified and q...
Source: Food Microbiology - September 26, 2017 Category: Food Science Authors: Meucci A, Rossetti L, Zago M, Monti L, Giraffa G, Carminati D, Tidona F Tags: Food Microbiol Source Type: research

Unravelling the contribution of the Penicillium expansum PeSte12 transcription factor to virulence during apple fruit infection.
onzález-Candelas L, Torres R Abstract Blue mould disease caused by Penicillium expansum infection is one of the most important diseases of pome fruit accounting for important economic losses. In the present study, the PeSte12 transcription factor gene was identified, and deletant mutants were produced by gene replacement. Knockout mutants showed a significant decrease of virulence during apple fruit infection. Virulence was affected by the maturity stage of the fruit (immature, mature and over-mature), and disease severity was notably reduced when the apples were stored at 0 °C. The ΔPeSte12 ...
Source: Food Microbiology - September 26, 2017 Category: Food Science Authors: Sánchez-Torres P, Vilanova L, Ballester AR, López-Pérez M, Teixidó N, Viñas I, Usall J, González-Candelas L, Torres R Tags: Food Microbiol Source Type: research

Development of non-pathogenic bacterial biofilms on the surface of stainless steel which are inhibitory to Salmonella enterica.
This study provides insights to developing strategies to inactivate Salmonella and perhaps other foodborne pathogens on abiotic surfaces using non-pathogenic antagonistic bacteria. PMID: 28941894 [PubMed - in process] (Source: Food Microbiology)
Source: Food Microbiology - September 26, 2017 Category: Food Science Authors: Kim Y, Kim H, Beuchat LR, Ryu JH Tags: Food Microbiol Source Type: research

Microbiological stabilization of tiger nuts' milk beverage using ultra-high pressure homogenization. A preliminary study on microbial shelf-life extension.
Abstract Tiger nuts' milk beverages are highly perishable products. For this reason, the interest of food industry for their commercialization makes necessary the application of preservation treatments to prolong their shelf-life. In the current study, the effect of ultra-high pressure homogenization (UHPH) on the microbiological and sensory qualities of tiger nuts' milk beverage was evaluated. Characteristics of UHPH-treated products (at 200 and 300 MPa, with inlet temperature of 40 °C) were compared with those of raw (RP) and conventionally homogenized-pasteurized (H-P) beverages, after treatment a...
Source: Food Microbiology - September 26, 2017 Category: Food Science Authors: Codina-Torrella I, Guamis B, Zamora A, Quevedo JM, Trujillo AJ Tags: Food Microbiol Source Type: research

Restoration of GABA production machinery in Lactobacillus brevis by accessible carbohydrates, anaerobiosis and early acidification.
Abstract Lactobacillus brevis is an efficient cell factory for producing bioactive γ-aminobutyric acid (GABA) by its gad operon-encoded glutamic acid decarboxylase (GAD) system. However, little mechanistic insights have been reported on the effects of carbohydrate, oxygen and early acidification on GABA production machinery in Lb. brevis. In the present study, GABA production from Lb. brevis was enhanced by accessible carbohydrates. Fast growth of this organism was stimulated by maltose and xylose. However, its GABA production was highly suppressed by oxygen exposure, but was fully restored by anaerobiosis t...
Source: Food Microbiology - September 26, 2017 Category: Food Science Authors: Wu Q, Shah NP Tags: Food Microbiol Source Type: research

Characterization of Aspergillus section Flavi isolated from fresh chestnuts and along the chestnut flour process.
Abstract An extensive sampling of Aspergillus section Flavi considered to be the main agent responsible for aflatoxin contamination, was carried out in the field and along the processing phases of chestnut flour production in 2015. Fifty-eight isolates were characterized by means of biological, molecular and chemical assays. The highest incidence of Aspergillus section Flavi was found in the field. The identification of the isolates was based on β-tubulin and calmodulin gene sequences. A. flavus was found to be the dominant species, and this was followed by A. oryzae var effusus, A. tamarii, A. para...
Source: Food Microbiology - September 26, 2017 Category: Food Science Authors: Prencipe S, Siciliano I, Contessa C, Botta R, Garibaldi A, Gullino ML, Spadaro D Tags: Food Microbiol Source Type: research

Interlaboratory validation of an improved method for detection of Cyclospora cayetanensis in produce using a real-time PCR assay.
Abstract A collaborative validation study was performed to evaluate the performance of a new U.S. Food and Drug Administration method developed for detection of the protozoan parasite, Cyclospora cayetanensis, on cilantro and raspberries. The method includes a sample preparation step in which oocysts are recovered from produce using an enhanced produce washing solution containing 0.1% Alconox and a commercially available method to disrupt the C. cayetanensis oocysts and extract DNA. A real-time PCR assay targeting the C. cayetanensis 18S rDNA gene with an internal amplification control to monitor PCR inh...
Source: Food Microbiology - September 26, 2017 Category: Food Science Authors: Murphy HR, Cinar HN, Gopinath G, Noe KE, Chatman LD, Miranda NE, Wetherington JH, Neal-McKinney J, Pires GS, Sachs E, Stanya KJ, Johnson CL, Nascimento FS, Santin M, Molokin A, Samadpour M, Janagama H, Kahler A, Miller C, da Silva AJ Tags: Food Microbiol Source Type: research

Oxygen availability and strain combination modulate yeast growth dynamics in mixed culture fermentations of grape must with Starmerella bacillaris and Saccharomyces cerevisiae.
This study reveals new knowledge about the influence of oxygen availability on the successional evolution of yeast species during wine fermentation. PMID: 28941899 [PubMed - in process] (Source: Food Microbiology)
Source: Food Microbiology - September 26, 2017 Category: Food Science Authors: Englezos V, Cravero F, Torchio F, Rantsiou K, Ortiz-Julien A, Lambri M, Gerbi V, Rolle L, Cocolin L Tags: Food Microbiol Source Type: research

Model for Listeria monocytogenes inactivation by high hydrostatic pressure processing in Spanish chorizo sausage.
o RM, Martínez B Abstract A central composite design was implemented to study the effect of three factors on HHP-induced L. monocytogenes inactivation in Spanish chorizo sausage, in order to increase its effectiveness: product aw (0.79-0.92), pressure intensities (349-600 MPa, at 18 °C) and holding time (0-12.53 min). Response surface methodology was implemented with backward stepwise regression to generate a model that best fitted to the experimental data. All the three factors studied significantly influenced HHP inactivation of L. monocytogenes (p 
Source: Food Microbiology - September 26, 2017 Category: Food Science Authors: Rubio B, Possas A, Rincón F, García-Gímeno RM, Martínez B Tags: Food Microbiol Source Type: research

Antimicrobial efficacy of phytochemicals against Bacillus cereus in reconstituted infant rice cereal.
The objective of this study was to determine the potential use of Trans-cinnamaldehyde (TC), (-)-Epigallocatechin gallate (EGCG) and [10]-Gingerol (GI) to inhibit the growth of B. cereus in infant rice cereal reconstituted with infant formula. Samples were inoculated with either vegetative cells or spores of B. cereus (ATCC 14579), and they were treated with 500 ppm (mg/L) TC, EGCG and GI. They were stored at 7 °C, 23 °C, or 37 °C for 0, 4, 8 and 24 h to simulate advance preparation, handling and temperature abuse. At 23 °C no growth was observed with TC over 24 ...
Source: Food Microbiology - September 26, 2017 Category: Food Science Authors: Cetin-Karaca H, Newman MC Tags: Food Microbiol Source Type: research

National survey of foodborne viruses in Australian oysters at production.
Abstract Internationally human enteric viruses, such as norovirus (NoV) and hepatitis A virus (HAV), are frequently associated with shellfish related foodborne disease outbreaks, and it has been suggested that acceptable NoV limits based on end-point testing be established for this high risk food group. Currently, shellfish safety is generally managed through the use of indicators of faecal contamination. Between July 2014 and August 2015, a national prevalence survey for NoV and HAV was done in Australian oysters suitable for harvest. Two sampling rounds were undertaken to determine baseline levels of these virus...
Source: Food Microbiology - September 26, 2017 Category: Food Science Authors: Torok V, Hodgson K, McLeod C, Tan J, Malhi N, Turnbull A Tags: Food Microbiol Source Type: research

Migration of Salmonella serotypes Heidelberg and Enteritidis in previously frozen chicken breast meat.
Abstract Salmonella spp. have been shown to migrate to the internal regions of meat cuts. Storage conditions and the presence of proteolytic microbiota can influence this process. Our study assessed the impact of storage time, temperature, and the presence of proteolytic psychrotrophic bacteria on migration. Samples of previously frozen chicken breast with skin and bone were then sterilized using gamma ray irradiation and a cobalt-60 source (11 KGy) and them were inoculated with cultures of S. Enteritidis, S. Enteritidis and psychrotrophs, S. Heidelberg, or S. Heidelberg and psychrotrophs. Inoculated samples ...
Source: Food Microbiology - September 26, 2017 Category: Food Science Authors: Tozzo K, Neto AFG, Spercoski KM, Ronnau M, Soares VM, Bersot LS Tags: Food Microbiol Source Type: research

Impact of growth temperature on exopolysaccharide production and probiotic properties of Lactobacillus paracasei strains isolated from kefir grains.
te GL Abstract EPS-producing LAB are widely used in the dairy industry since these polymers improve the viscosity and texture of the products. Besides, EPS might be responsible for several health benefits attributed to probiotic strains. However, growth conditions (culture media, temperature, pH) could modify EPS production affecting both technological and probiotic properties. In this work, the influence of growth temperature on EPS production was evaluated, as well as the consequences of these changes in the probiotic properties of the strains. All Lactobacillus paracasei strains used in the study showed changes...
Source: Food Microbiology - September 26, 2017 Category: Food Science Authors: Bengoa AA, Llamas MG, Iraporda C, Dueñas MT, Abraham AG, Garrote GL Tags: Food Microbiol Source Type: research

Redefining the effect of salt on thermophilic starter cell viability, culturability and metabolic activity in cheese.
This study investigated the differential effect of salt concentration in the outside and inside layers of brine salted cheeses on viability, culturability and enzyme activity of starter bacteria. The high-salt environment of the outside layer caused a sharp decrease in L. helveticus viability as measured by traditional plate counts. Remarkably, this was associated with lower release of intracellular enzymes (LDH), reduced levels of proteolysis and larger membrane integrity as measured by flow cytometry (FC) following classical Live/Dead staining. FC analysis of light scattering properties highlighted a significant red...
Source: Food Microbiology - September 26, 2017 Category: Food Science Authors: Hickey CD, Fallico V, Wilkinson MG, Sheehan JJ Tags: Food Microbiol Source Type: research

Internalization and dissemination of human norovirus and Tulane virus in fresh produce is plant dependent.
In this study we compared the internalization and dissemination rates of human NoV and its surrogate, Tulane virus (TV) in green onion, radishes, and Romaine lettuce. We also evaluated the effect inoculum level and plant growth matrix on the rate of viral internalization. In the hydroponic growth system, we detected internalization and dissemination of human NoV RNA in green onions. In hydroponically growing green onions inoculated with high titer TV, we found higher rates of internalization and dissemination compared to green onions inoculated with low titer TV. In soil growth systems, no infectious TV was detected in eit...
Source: Food Microbiology - September 26, 2017 Category: Food Science Authors: Yang Z, Chambers H, DiCaprio E, Gao G, Li J Tags: Food Microbiol Source Type: research

Genotyping, identification and multifunctional features of yeasts associated to Bosana naturally black table olive fermentations.
Mannazzu I, Arroyo-López FN Abstract Directly brined black table olives of Bosana variety are a traditional food product of Sardinia island (Italy), spontaneously fermented by yeasts among other microorganisms. However, as far as we know, the identification, biotechnological and probiotic potential of this yeast community has not been investigated yet. In this work, a total of 72 yeast isolates previously obtained from Bosana olive brines were first genotyped by Random Amplified Polymorphic DNA (RAPD-PCR) analysis with primer M13, and then identified by sequencing of D1/D2 domains of rDNA 26S gene. The dom...
Source: Food Microbiology - September 26, 2017 Category: Food Science Authors: Porru C, Rodríguez-Gómez F, Benítez-Cabello A, Jiménez-Díaz R, Zara G, Budroni M, Mannazzu I, Arroyo-López FN Tags: Food Microbiol Source Type: research

Prevalence of Staphylococcus aureus and of methicillin-resistant S.  aureus (MRSA) along the production chain of dairy products in north-western Greece.
The objective of this study was to estimate the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in the production chain of dairy products. Of 367 tested samples (36 bulk tank milk (BTM), 19 dairy products, 72 human, 185 animal, 55 equipment), 212 (57.8%) were found positive for S. aureus. Almost all isolates (99.6%) were resistant to at least one antimicrobial and 13.3% were multi-drug resistant (MDR), exhibiting resistance to three or more antibiotic classes. Eleven samples (3%) were found contaminated by MRSA carrying the mecA gene. None of the MRSA isolates carried the mecC or the Pandon-Valentine ...
Source: Food Microbiology - September 26, 2017 Category: Food Science Authors: Papadopoulos P, Papadopoulos T, Angelidis AS, Boukouvala E, Zdragas A, Papa A, Hadjichristodoulou C, Sergelidis D Tags: Food Microbiol Source Type: research

Use of non-Saccharomyces yeasts and oenological tannin in red winemaking: Influence on colour, aroma and sensorial properties of young wines.
ito S Abstract Today, many non-Saccharomyces strains have been verified can be positive for the development of wine anthocyanin and aroma in different fermentation scenarios. Moreover, oenological tannins are widely used in wine industry to improve the colour profile and aroma complexity. The aim of this work is to analyze the fermentation characters of non-Saccharomyces strains and investigate the effects of pre-fermentative addition of oenological tannins on the wine components as well as sensory properties. For this purpose, five selected non-Saccharomyces strains and grape seed tannin were used to carry out th...
Source: Food Microbiology - September 26, 2017 Category: Food Science Authors: Chen K, Escott C, Loira I, Del Fresno JM, Morata A, Tesfaye W, Calderon F, Suárez-Lepe JA, Han S, Benito S Tags: Food Microbiol Source Type: research

Bicarbonate and amino acids are co-germinants for spores of Clostridium perfringens type A isolates carrying plasmid-borne enterotoxin gene.
Abstract Clostridium perfringens type A isolates carrying a chromosomal enterotoxin (cpe) gene (C-cpe) are generally linked to food poisoning, while isolates carrying cpe on a plasmid (P-cpe) are associated with non-food-borne gastrointestinal diseases. Both C-cpe and P-cpe isolates can form metabolically dormant spores, which through germination process return to actively growing cells to cause diseases. In our previous study, we showed that only 3 out of 20 amino acids (aa) in phosphate buffer (pH 7.0) triggered germination of spores of P-cpe isolates (P-cpe spores). We now found that 14 out of 20 individual aa ...
Source: Food Microbiology - September 26, 2017 Category: Food Science Authors: Alnoman M, Udompijitkul P, Banawas S, Sarker MR Tags: Food Microbiol Source Type: research

A model for the influences of soluble and insoluble solids, and treated volume on the ultraviolet-C resistance of heat-stressed Salmonella enterica in simulated fruit juices.
This study was conducted to determine the effects of intrinsic juice characteristics namely insoluble solids (IS, 0-3 %w/v), and soluble solids (SS, 0-70 °Brix), and extrinsic process parameter treated volume (250-1000 mL) on the UV-C inactivation rates of heat-stressed Salmonella enterica in simulated fruit juices (SFJs). A Rotatable Central Composite Design of Experiment (CCRD) was used to determine combinations of the test variables, while Response Surface Methodology (RSM) was used to characterize and quantify the influences of the test variables on microbial inactivation. The heat-stressed cells exhibited log...
Source: Food Microbiology - September 26, 2017 Category: Food Science Authors: Estilo EEC, Gabriel AA Tags: Food Microbiol Source Type: research

Desiccation: An environmental and food industry stress that bacteria commonly face.
aud M Abstract Water is essential for all living organisms, for animals as well as for plants and micro-organisms. For these latter, the presence of water or a humid environment with a high air relative humidity (RH) is necessary for their survival and growth. Thus, variations in the availability of water or in the air relative humidity constitute widespread environmental stresses which challenge microorganisms, and especially bacteria. Indeed, in their direct environment, bacteria are often faced with conditions that remove cell-bound water through air-drying of the atmosphere. Bacterial cells are subject to dail...
Source: Food Microbiology - September 26, 2017 Category: Food Science Authors: Esbelin J, Santos T, Hébraud M Tags: Food Microbiol Source Type: research

Sea salts as a potential source of food spoilage fungi.
This study aimed to determine whether finished salts contain viable fungi that have the potential to cause spoilage when sea salt is used as a food ingredient by isolating fungi on a medium that simulated salted food with a lowered water activity (0.95 aw). The viable filamentous fungi from seven commercial salts were quantified and identified by DNA sequencing, and the fungal communities in different salts were compared. Every sea salt tested contained viable fungi, in concentrations ranging from 0.07 to 1.71 colony-forming units per gram of salt. In total, 85 fungi were isolated representing seven genera. One or mor...
Source: Food Microbiology - September 26, 2017 Category: Food Science Authors: Biango-Daniels MN, Hodge KT Tags: Food Microbiol Source Type: research

A novel approach in acidic disinfection through inhibition of acid resistance mechanisms; Maleic acid-mediated inhibition of glutamate decarboxylase activity enhances acid sensitivity of Listeria monocytogenes.
Abstract Here it is demonstrated a novel approach in disinfection regimes where specific molecular acid resistance systems are inhibited aiming to eliminate microorganisms under acidic conditions. Despite the importance of the Glutamate Decarboxylase (GAD) system for survival of Listeria monocytogenes and other pathogens under acidic conditions, its potential inhibition by specific compounds that could lead to its elimination from foods or food preparation premises has not been studied. The effects of maleic acid on the acid resistance of L. monocytogenes were investigated and found that it has a higher antim...
Source: Food Microbiology - September 26, 2017 Category: Food Science Authors: Paudyal R, Barnes RH, Karatzas KAG Tags: Food Microbiol Source Type: research

An investigation of vtx2 bacteriophage transduction to different Escherichia coli patho-groups in food matrices and nutrient broth.
This study investigated bacteriophage (phage) mediated transfer of the vtx2 gene from a donor Escherichia coli (C600φ3538(Δvtx2::cat)) to enteropathogenic (EPEC), enterotoxigenic (ETEC), enteroaggregative (EAEC), enteroinvasive (EIEC) and diffusely adherent (DAEC) E. coli strains in LB broth, milk, ground beef and lettuce. Two bacterial concentrations for both the E. coli donor and recipient strains, 3 and 5 log10 CFU/ml (LB broth and milk)/g (beef) or/cm(2) (lettuce), were used. When transductants were obtained, the location of insertion of the phage (insertion sites wrbA, yehA, sbcB, yecE and/or ...
Source: Food Microbiology - August 14, 2017 Category: Food Science Authors: Nyambe S, Burgess C, Whyte P, Bolton D Tags: Food Microbiol Source Type: research

Selection of reference genes to quantify relative expression of ochratoxin A-related genes by Penicillium nordicum in dry-cured ham.
The objective of this study was to examine reference genes suitable for normalisation in designing and developing new RT-qPCR methods for quantifying the relative expression of genes involved in OTA biosynthesis (otapks and otanps) by P. nordicum on a dry-cured ham model system after 7 days of incubation. Firstly, primers based on three housekeeping genes commonly found in moulds, β-tubulin, COI and ITS, and on the otapks gene were designed. The primer pair F/R-npstr previously developed on the otanps gene was also used. Although most of the designed primers met the requirements needed to be used in qPCR assays, ...
Source: Food Microbiology - August 14, 2017 Category: Food Science Authors: Bernáldez V, Córdoba JJ, Andrade MJ, Alía A, Rodríguez A Tags: Food Microbiol Source Type: research

Characterization of a novel endolysin LysSA11 and its utility as a potent biocontrol agent against Staphylococcus aureus on food and utensils.
Abstract Here we show that the LysSA11 endolysin, derived from the virulent Staphylococcus aureus phage SA11, has lytic activity against staphylococcal strains. Bioinformatics analysis revealed an enzymatically active CHAP (cysteine, histidine-dependent amidohydrolases/peptidases) domain at the N-terminus of LysSA11 that showed amidase activity. A novel cell wall binding domain (CBD) in the C-terminus could bind to a broad spectrum of staphylococcal cells. The bactericidal activity of LysSA11 was determined in food and utensils artificially contaminated with methicillin-resistant S. aureus (MRSA). The amounts...
Source: Food Microbiology - August 14, 2017 Category: Food Science Authors: Chang Y, Kim M, Ryu S Tags: Food Microbiol Source Type: research

Estimation of the probability of bacterial population survival: Development of a probability model to describe the variability in time to inactivation of Salmonella enterica.
Abstract Despite the development of numerous predictive microbial inactivation models, a model focusing on the variability in time to inactivation for a bacterial population has not been developed. Additionally, an appropriate estimation of the risk of there being any remaining bacterial survivors in foods after the application of an inactivation treatment has not yet been established. Here, Gamma distribution, as a representative probability distribution, was used to estimate the variability in time to inactivation for a bacterial population. Salmonella enterica serotype Typhimurium was evaluated for survival in ...
Source: Food Microbiology - August 14, 2017 Category: Food Science Authors: Koyama K, Hokunan H, Hasegawa M, Kawamura S, Koseki S Tags: Food Microbiol Source Type: research

Bacterial diversity of the Colombian fermented milk "Suero Coste ño" assessed by culturing and high-throughput sequencing and DGGE analysis of 16S rRNA gene amplicons.
Bacterial diversity of the Colombian fermented milk "Suero Costeño" assessed by culturing and high-throughput sequencing and DGGE analysis of 16S rRNA gene amplicons. Food Microbiol. 2017 Dec;68:129-136 Authors: Motato KE, Milani C, Ventura M, Valencia FE, Ruas-Madiedo P, Delgado S Abstract "Suero Costeño" (SC) is a traditional soured cream elaborated from raw milk in the Northern-Caribbean coast of Colombia. The natural microbiota that characterizes this popular Colombian fermented milk is unknown, although several culturing studies have previously been attempted. In...
Source: Food Microbiology - August 14, 2017 Category: Food Science Authors: Motato KE, Milani C, Ventura M, Valencia FE, Ruas-Madiedo P, Delgado S Tags: Food Microbiol Source Type: research

Listeria monocytogenes incidence changes and diversity in some Brazilian dairy industries and retail products.
Abstract Listeria monocytogenes can cause listeriosis, a severe foodborne disease. In Brazil, despite very few reported cases of listeriosis, the pathogen has been repeatedly isolated from dairies. This has led the government to implement specific legislation to reduce the hazard. Here, we determined the incidence of L. monocytogenes in five dairies and retail products in the Southeast and Midwest regions of Brazil over eight months. Of 437 samples, three samples (0.7%) from retail and only one sample (0.2%) from the dairies were positive for L. monocytogenes. Thus, the contamination rate was significant...
Source: Food Microbiology - August 14, 2017 Category: Food Science Authors: Oxaran V, Lee SHI, Chaul LT, Corassin CH, Barancelli GV, Alves VF, de Oliveira CAF, Gram L, De Martinis ECP Tags: Food Microbiol Source Type: research

Escherichia coli transfer from simulated wildlife feces to lettuce during foliar irrigation: A field study in the Northeastern United States.
This study was performed to calculate transfer coefficients for Escherichia coli from simulated wildlife feces to field-grown lettuce during irrigation. Rabbit feces inoculated with a 3-strain cocktail of non-pathogenic E. coli were placed in a lettuce field 2.5-72 h before irrigation. Following irrigation, the E. coli concentration on the lettuce was determined. After exclusion of an outlier with high E. coli levels (Most Probable Number = 5.94*10(8)), the average percent of E. coli in the feces that transferred to intact lettuce heads was 0.0267% (Standard Error [SE] = 0.0172)...
Source: Food Microbiology - August 14, 2017 Category: Food Science Authors: Weller DL, Kovac J, Kent DJ, Roof S, Tokman JI, Mudrak E, Kowalcyk B, Oryang D, Aceituno A, Wiedmann M Tags: Food Microbiol Source Type: research

Detection and quantification of Alicyclobacillus acidoterrestris by electrical impedance in apple juice.
This study aimed at developing a more accurate electrical impedance technique for the detection of A. acidoterrestris in concentrated apple juice. Samples of apple juice were inoculated with A. acidoterrestris spores isolated from a peach and grape juice. For the spore germination, several heat-shock treatments were tested (80 °C/10 min, 70 °C/20 min and 60 °C/30 min). Direct and indirect electrical impedance was applied to detect and quantify the microorganism in the inoculated apple juice, using BAT broth and Bimedia 002A (pH 4). The 80 °C/10 min treatment was selected for sp...
Source: Food Microbiology - August 14, 2017 Category: Food Science Authors: Fernández P, Gabaldón JA, Periago MJ Tags: Food Microbiol Source Type: research

Assessing the antimicrobial potential of aerosolised electrochemically activated solutions (ECAS) for reducing the microbial bio-burden on fresh food produce held under cooled or cold storage conditions.
Abstract The main aim of this study was to assess the antimicrobial efficacy of electrochemically activated fog (ECAF) for reducing the microbial bio-burden on artificially inoculated fresh produce held under cooled (cucumber and vine tomatoes) or cold (rocket and broccoli) storage conditions. The ECAF treatment (1100 ± 5 mV ORP; 50 ± 5 mg L(-1) free chlorine; 2.7 ± 0.1 pH) resulted in a significant log reduction in the potential pathogen E. coli recovered from rocket (2.644 Log10 CFU g(-1)), broccoli (4.204 Log10 CFU g(-1))...
Source: Food Microbiology - August 14, 2017 Category: Food Science Authors: Thorn RMS, Pendred J, Reynolds DM Tags: Food Microbiol Source Type: research

Efficacy evaluation of a new water sanitizer for increasing the shelf life of Southern Australian King George Whiting and Tasmanian Atlantic Salmon fillets.
Abstract The bacterial species and specific spoilage organisms associated with the Southern Australian King George Whiting (KGW) and Tasmanian Atlantic Salmon (TAS), and the efficacy of a HOCl-containing water-based sanitization product (Electro-Chemically Activated Solution, by ECAS4) in extending the shelf life of KGW and TAS fillets were evaluated. Fillets were washed with an ECAS4 solution containing either 45 ppm or 150 ppm of free chlorine and bacterial species enumerated on selective and non-selective media, followed by identification of pure isolates by 16 S rRNA gene sequencing. The dominan...
Source: Food Microbiology - August 14, 2017 Category: Food Science Authors: Khazandi M, Deo P, Ferro S, Venter H, Pi H, Crabb S, Amorico T, Ogunniyi AD, Trott DJ Tags: Food Microbiol Source Type: research

Effect of thyme essential oil and Lactococcus lactis CBM21 on the microbiota composition and quality of minimally processed lamb's lettuce.
Abstract The main aim of this work was to evaluate, at pilot scale in an industrial environment, the effects of the biocontrol agent Lactococcus lactis CBM21 and thyme essential oil compared to chlorine, used in the washing step of fresh-cut lamb's lettuce, on the microbiota and its changes in relation to the time of storage. The modification of the microbial population was studied through pyrosequencing in addition to the traditional plate counts. In addition, the volatile molecule and sensory profiles were evaluated during the storage. The results showed no significant differences in terms of total aerobic mesop...
Source: Food Microbiology - August 14, 2017 Category: Food Science Authors: Siroli L, Patrignani F, Serrazanetti DI, Vernocchi P, Del Chierico F, Russo A, Torriani S, Putignani L, Gardini F, Lanciotti R Tags: Food Microbiol Source Type: research

Modelling the effect of water activity reduction by sodium chloride or glycerol on conidial germination and radial growth of filamentous fungi encountered in dairy foods.
Abstract Water activity (aw) is one of the most influential abiotic factors affecting fungal development in foods. The effects of aw reduction on conidial germination and radial growth are generally studied by supplementing culture medium with the non-ionic solute glycerol despite food aw can also depend on the concentration of ionic solutes such as sodium chloride (NaCl). The present study aimed at modelling and comparing the effects of aw, either modified using NaCl or glycerol, on radial growth and/or conidial germination parameters for five fungal species occurring in the dairy environment. The estimated cardi...
Source: Food Microbiology - August 14, 2017 Category: Food Science Authors: Nguyen Van Long N, Rigalma K, Coroller L, Dadure R, Debaets S, Mounier J, Vasseur V Tags: Food Microbiol Source Type: research

Culture-dependent and culture-independent assessment of spoilage community growth on VP lamb meat from packaging to past end of shelf-life.
In this study the shelf-life of VP bone-in lamb hind shanks stored at 8 °C and -1.2 °C was determined in parallel to analyses of starting and eventual spoilage bacterial communities via Illumina MiSeq based 16S rRNA amplicon sequencing. The mean total viable counts (TVC) and lactic acid bacterial viable counts (LAB) were observed to increase to log 7.5 CFU/cm(2) and 7 CFU/cm(2) after 6 and 42 days at 8 °C and -1.2 °C and stayed stable until shelf-life termination after 13 and 124 days, respectively. The sequence data showed initial communities were patchily distribute...
Source: Food Microbiology - August 14, 2017 Category: Food Science Authors: Kaur M, Shang H, Tamplin M, Ross T, Bowman JP Tags: Food Microbiol Source Type: research

Combination of endolysins and high pressure to inactivate Listeria monocytogenes.
Abstract Outbreaks of listeriosis are often related to the consumption of low-processed ready-to-eat food products (e.g. soft cheeses or smoked fish) contaminated with Listeria monocytogenes. Traditional preservation techniques, such as heat treatment, cannot eliminate Listeria from these products without strongly affecting the quality of the foods. We therefore investigated the use of endolysin (PlyP40, Ply511, or PlyP825) in combination with high hydrostatic pressure processing to kill L. monocytogenes in buffer. The results demonstrated a more than additive effect when both treatments were combined. For ex...
Source: Food Microbiology - August 14, 2017 Category: Food Science Authors: van Nassau TJ, Lenz CA, Scherzinger AS, Vogel RF Tags: Food Microbiol Source Type: research

Modeling carbon dioxide effect in a controlled atmosphere and its interactions with temperature and pH on the growth of L.  monocytogenes and P. fluorescens.
Modeling carbon dioxide effect in a controlled atmosphere and its interactions with temperature and pH on the growth of L. monocytogenes and P. fluorescens. Food Microbiol. 2017 Dec;68:89-96 Authors: Couvert O, Guégan S, Hézard B, Huchet V, Lintz A, Thuault D, Stahl V Abstract The effect of carbon dioxide, temperature, and pH on growth of Listeria monocytogenes and Pseudomonas fluorescens was studied, following a protocol to monitor microbial growth under a constant gas composition. In this way, the CO2 dissolution didn't modify the partial pressures in the gas phase. Growth cu...
Source: Food Microbiology - August 14, 2017 Category: Food Science Authors: Couvert O, Guégan S, Hézard B, Huchet V, Lintz A, Thuault D, Stahl V Tags: Food Microbiol Source Type: research

Characterization of Enterococcus durans 152 bacteriocins and their inhibition of Listeria monocytogenes in ham.
In this study, the two bacteriocins produced by E. durans 152 were characterized and identified as Dur 152A (an enterocin L50A derivative with two amino acid substitutions of I→M) and enterocin L50B. The bacteriocins were then partially purified and evaluated for inhibitory activity to L. monocytogenes in deli ham. Results revealed that at 400 AU/ml, the bacteriocins prevented growth of listeria in deli ham for at least 10 weeks at 8 °C and at least 30 days at 15 °C. For comparison, 500 ppm Nisin controlled listeria growth for up to 6 weeks at 8 °C and up t...
Source: Food Microbiology - August 14, 2017 Category: Food Science Authors: Du L, Liu F, Zhao P, Zhao T, Doyle MP Tags: Food Microbiol Source Type: research

Yeast diversity during the fermentation of Andean chicha: A comparison of high-throughput sequencing and culture-dependent approaches.
Abstract Diversity and dynamics of yeasts associated with the fermentation of Argentinian maize-based beverage chicha was investigated. Samples taken at different stages from two chicha productions were analyzed by culture-dependent and culture-independent methods. Five hundred and ninety six yeasts were isolated by classical microbiological methods and 16 species identified by RFLPs and sequencing of D1/D2 26S rRNA gene. Genetic typing of isolates from the dominant species, Saccharomyces cerevisiae, by PCR of delta elements revealed up to 42 different patterns. High-throughput sequencing (HTS) of D1/D2 26S rRNA g...
Source: Food Microbiology - June 28, 2017 Category: Food Science Authors: Mendoza LM, Neef A, Vignolo G, Belloch C Tags: Food Microbiol Source Type: research

Biodiversity and ochratoxin A profile of Aspergillus section Nigri populations isolated from wine grapes in Cyprus vineyards.
The objective of this study was to evaluate the biodiversity of Aspergillus section Nigri populations from Cyprus vineyards by morphological, toxigenic and phylogenetic analysis. Aspergillus section Nigri populations were isolated from grapes of the varieties 'Maratheftiko' and 'Cabernet Sauvignon' originating from six growing regions of Cyprus during 2010 and 2011 years. The isolation frequency of Aspergillus section Nigri from grape samples was 43.3% and a total of 284 isolates were selected for further analyses based on the macroscopic characteristics of black aspergilli. The isolates were characterized by sequencing an...
Source: Food Microbiology - June 28, 2017 Category: Food Science Authors: Pantelides IS, Aristeidou E, Lazari M, Tsolakidou MD, Tsaltas D, Christofidou M, Kafouris D, Christou E, Ioannou N Tags: Food Microbiol Source Type: research