Heat resistance of Salmonella enterica is increased by pre-adaptation to peanut oil or sub-lethal heat exposure.
Abstract Cross-protection represents a considerable challenge in the food industry where hurdled interventions are often employed to reduce Salmonella contamination. The heat resistance of Salmonella strains from five serotypes (i.e., Typhimurium, Enteritidis, Tennessee, Thompson and Hartford) at 70 °C was determined by measurement of viable cell populations before and after adaptation to two common stresses employed in low-water activity food processing, desiccation and sub-lethal heat treatment. Survival of Salmonella at 70 °C significantly increased (p 
Source: Food Microbiology - May 25, 2016 Category: Food Science Authors: Fong K, Wang S Tags: Food Microbiol Source Type: research

Corrigendum to "Development of a predictive model for the growth kinetics of aerobic microbial population on pomegranate marinated chicken breast fillets under isothermal and dynamic temperature conditions" [Food Microbiol. 55 (2016) 25-31].
Corrigendum to "Development of a predictive model for the growth kinetics of aerobic microbial population on pomegranate marinated chicken breast fillets under isothermal and dynamic temperature conditions" [Food Microbiol. 55 (2016) 25-31]. Food Microbiol. 2016 Sep;58:148 Authors: Lytou A, Panagou EZ, Nychas GE PMID: 27217371 [PubMed - as supplied by publisher] (Source: Food Microbiology)
Source: Food Microbiology - May 25, 2016 Category: Food Science Authors: Lytou A, Panagou EZ, Nychas GE Tags: Food Microbiol Source Type: research

1-Octanol, a self-inhibitor of spore germination in Penicillium camemberti.
In this study, spore germination was shown to be self-regulated by quorum sensing in P. camemberti. This phenomenon, also called "crowding effect", is population-dependent (i.e. observed at high population densities). After determining the volatile nature of the compounds involved in this process, 1-octanol was identified as the main compound produced at high-spore density using GC-MS. Its inhibitory effect was confirmed in vitro and 3 mM 1-octanol totally inhibited spore germination while 100 μM only transiently inhibited spore germination. This is the first time that self-inhibition of sp...
Source: Food Microbiology - April 9, 2016 Category: Food Science Authors: Gillot G, Decourcelle N, Dauer G, Barbier G, Coton E, Delmail D, Mounier J Tags: Food Microbiol Source Type: research

Microbial dynamics during shelf-life of industrial Ricotta cheese and identification of a Bacillus strain as a cause of a pink discolouration.
Abstract Dairy products are perishable and have to be preserved from spoilage during the food chain to achieve the desired shelf-life. Ricotta is a typical Italian soft dairy food produced by heat coagulation of whey proteins and is considered to be a light and healthy product. The shelf-life of Ricotta could be extended, as required by the international food trade market; however, heat resistant microflora causes spoilage and poses issues regarding the safety of the product. Next-generation sequencing (NGS) applied to the Ricotta samples defined the composition of the microbial community in-depth during the shelf...
Source: Food Microbiology - April 9, 2016 Category: Food Science Authors: Sattin E, Andreani NA, Carraro L, Fasolato L, Balzan S, Novelli E, Squartini A, Telatin A, Simionati B, Cardazzo B Tags: Food Microbiol Source Type: research

Lysozyme affects the microbial catabolism of free arginine in raw-milk hard cheeses.
Abstract Lysozyme (LZ) is used in several cheese varieties to prevent late blowing which results from fermentation of lactate by Clostridium tyrobutyricum. Side effects of LZ on lactic acid bacteria population and free amino acid pattern were studied in 16 raw-milk hard cheeses produced in eight parallel cheese makings conducted at four different dairies using the same milk with (LZ+) or without (LZ-) addition of LZ. The LZ-cheeses were characterized by higher numbers of cultivable microbial population and lower amount of DNA arising from lysed bacterial cells with respect to LZ + cheeses. At both 9 and ...
Source: Food Microbiology - April 9, 2016 Category: Food Science Authors: D'Incecco P, Gatti M, Hogenboom JA, Bottari B, Rosi V, Neviani E, Pellegrino L Tags: Food Microbiol Source Type: research

Occurrence of potentially pathogenic arcobacters in shellfish.
Di Pinto A Abstract Considering that several recent cases of human gastroenteritis have been associated with species from the Arcobacter genus, and that few data are currently available about the occurrence of this genus in Italian shellfish, the aim of the present study was to evaluate the occurrence of Arcobacter spp. and the presence of virulence-associated genes. The approach consisted of cultural and biomolecular (multiplex-PCR and 16S-RFLP) methods identifying isolates, followed by PCR assays aimed at the cadF, ciaB, cjl349, irgA, hecA putative virulence genes. Arcobacter spp. was detected in 16/70 (22.8%) ...
Source: Food Microbiology - April 9, 2016 Category: Food Science Authors: Mottola A, Bonerba E, Figueras MJ, Pérez-Cataluña A, Marchetti P, Serraino A, Bozzo G, Terio V, Tantillo G, Di Pinto A Tags: Food Microbiol Source Type: research

Development and application of Geobacillus stearothermophilus growth model for predicting spoilage of evaporated milk.
This study was undertaken to provide an approach in modelling the effect of temperature on G. stearothermophilus ATCC 7953 growth and in predicting spoilage of evaporated milk. The growth of G. stearothermophilus was monitored in tryptone soy broth at isothermal conditions (35-67 °C). The data derived were used to model the effect of temperature on G. stearothermophilus growth with a cardinal type model. The cardinal values of the model for the maximum specific growth rate were Tmin = 33.76 °C, Tmax = 68.14 °C, Topt = 61.82 °C and μopt ...
Source: Food Microbiology - April 9, 2016 Category: Food Science Authors: Kakagianni M, Gougouli M, Koutsoumanis KP Tags: Food Microbiol Source Type: research

Simultaneous detection of the protozoan parasites Toxoplasma, Cryptosporidium and Giardia in food matrices and their persistence on basil leaves.
In this study, a new immunomagnetic separation assay (IMS Toxo) targeting the oocyst's wall of T. gondii was developed using a specific purified monoclonal antibody. Performance of this IMS Toxo coupled to microscopic and qPCR analyses was evaluated in terms of limit of detection (LOD) and recovery rate (RR) on: i) simple matrix (LOD = 5 oocysts; RR between 5 and 56%); ii) raspberries and basil (LOD = 33 oocysts/g; RR between 0.2 and 35%). Finally, to simultaneously extract the three protozoa from these food matrices, T. gondii oocysts were directly concentrated (without IMS Toxo) from the sup...
Source: Food Microbiology - April 9, 2016 Category: Food Science Authors: Hohweyer J, Cazeaux C, Travaillé E, Languet E, Dumètre A, Aubert D, Terryn C, Dubey JP, Azas N, Houssin M, Loïc F, Villena I, La Carbona S Tags: Food Microbiol Source Type: research

Yeasts isolated from figs (Ficus carica L.) as biocontrol agents of postharvest fruit diseases.
ernández A Abstract Fresh fruit is highly perishable during postharvest life, mainly due to fungal growth. Thus, fungal control is an important goal for the fruit industry. In this work, a selection of antagonistic yeasts isolated from fig and breba crops were screened in vitro. The isolated yeasts were challenged with three moulds isolated from decayed figs and breba crops, identified as Penicillium expansum M639 and Cladosporium cladosporioides M310 and M624, and pathogenic moulds Botrytis cinerea CECT20518 and Monilia laxa CA1 from culture collections. Two yeast isolates, Hanseniaspora opuntiae L479...
Source: Food Microbiology - April 9, 2016 Category: Food Science Authors: Ruiz-Moyano S, Martín A, Villalobos MC, Calle A, Serradilla MJ, Córdoba MG, Hernández A Tags: Food Microbiol Source Type: research

Quantification of viable bacterial starter cultures of Virgibacillus sp. and Tetragenococcus halophilus in fish sauce fermentation by real-time quantitative PCR.
Abstract Real-time quantitative polymerase chain reaction (qPCR) methods were developed for the quantification of Virgibacillus sp. SK37 and Tetragenococcus halophilus MS33, which were added as starter cultures in fish sauce fermentation. The PCR assays were coupled with propidium monoazide (PMA) treatment of samples to selectively quantify viable cells and integrated with exogenous recombinant Escherichia coli cells to control variabilities in analysis procedures. The qPCR methods showed species-specificity for both Virgibacillus halodenitrificans and T. halophilus as evaluated using 6 reference strains and ...
Source: Food Microbiology - April 9, 2016 Category: Food Science Authors: Udomsil N, Chen S, Rodtong S, Yongsawatdigul J Tags: Food Microbiol Source Type: research

Phaeobacter inhibens as biocontrol agent against Vibrio vulnificus in oyster models.
Abstract Molluscan shellfish can cause food borne diseases and here we investigated if addition of Vibrio-antagonising bacteria could reduce Vibrio vulnificus in model oyster systems and prevent its establishment in live animals. Phaeobacter inhibens, which produces an antibacterial compound, tropodithietic acid (TDA), inhibited V. vulnificus as did pure TDA (MIC of 1-3.9 μM). P. inhibens DSM 17395 (at 10(6) cfu/ml) eradicated 10(5) cfu/ml V. vulnificus CMCP6 (a rifampicin resistant variant) from a co-culture oyster model system (oyster juice) whereas the pathogen grew to 10(7) cfu...
Source: Food Microbiology - April 9, 2016 Category: Food Science Authors: Porsby CH, Gram L Tags: Food Microbiol Source Type: research

Effect of zinc formulations, sodium chloride, and hydroxytyrosol on the growth/no-growth boundaries of table olive related yeasts.
This study uses a mathematical approach to assessing the inhibitory effect of Zn(2)(+)(0-10 mM, obtained from ZnCl2 and ZnSO4) in presence of NaCl (0-8%) and hydroxytyrosol (0-2588 mg/L), on a yeast cocktail formed by species Pichia galeiformis, Pichia kudriavzevii, Pichia manshurica and Candida thaimueangensis obtained from spoilt green olive packages. The logistic/probabilistic models were built in laboratory medium using a total of 1980 responses (1188 for NaCl and 792 for hydroxytyrosol). ZnCl2 showed significantly higher inhibitory effect than ZnSO4 in the presence of both NaCl (p 
Source: Food Microbiology - April 9, 2016 Category: Food Science Authors: Romero-Gil V, Rejano-Zapata L, Garrido-Fernández A, Arroyo-López FN Tags: Food Microbiol Source Type: research

Curli fimbriae are conditionally required in Escherichia coli O157:H7 for initial attachment and biofilm formation.
Abstract Several species of enteric pathogens produce curli fimbriae, which may affect their interaction with surfaces and other microbes in nonhost environments. Here we used two Escherichia coli O157:H7 outbreak strains with distinct genotypes to understand the role of curli in surface attachment and biofilm formation in several systems relevant to fresh produce production and processing. Curli significantly enhanced the initial attachment of E. coli O157:H7 to spinach leaves and stainless steel surfaces by 5-fold. Curli was also required for E. coli O157:H7 biofilm formation on stainless steel and enh...
Source: Food Microbiology - April 9, 2016 Category: Food Science Authors: Carter MQ, Louie JW, Feng D, Zhong W, Brandl MT Tags: Food Microbiol Source Type: research

Inhibition of Listeria monocytogenes on cooked cured chicken breasts by acidified coating containing allyl isothiocyanate or deodorized Oriental mustard extract.
This study screened 5 L. monocytogenes strains for their ability to hydrolyze sinigrin (a glucosinolate in Oriental mustard), which formed allyl isothiocyanate (AITC) and reduced L. monocytogenes viability on inoculated vacuum-packed, cooked, cured roast chicken slices at 4 °C. Tests involved incorporation of 25-50 μl/g AITC directly or 100-250 mg/g Oriental mustard extract in 0.5% (w/v) κ-carrageenan/2% (w/v) chitosan-based coatings prepared using 1.5% malic or acetic acid. L. monocytogenes strains hydrolyzed 33.6%-48.4% pure sinigrin in MH broth by 21 d at 25 °...
Source: Food Microbiology - April 9, 2016 Category: Food Science Authors: Olaimat AN, Holley RA Tags: Food Microbiol Source Type: research

Effect of the food matrix on pressure resistance of Shiga-toxin producing Escherichia coli.
This study compared the resistance of two five-strain E. coli cocktails, as well as the pressure resistant strain E. coli AW1.7, to hydrostatic pressure application in bruschetta, tzatziki, yoghurt and ground beef at 600 MPa, 20 °C for 3 min and during post-pressure survival at 4 °C. Pressure reduced STEC in plant and dairy products by more than 5 logs (cfu/ml) but not in ground beef. The pH affected the resistance of STEC to pressure as well as the post-pressure survival. E. coli with food constituents including calcium, magnesium, glutamate, caffeic acid and acetic acid were tre...
Source: Food Microbiology - April 9, 2016 Category: Food Science Authors: Li H, Garcia-Hernandez R, Driedger D, McMullen LM, Gänzle M Tags: Food Microbiol Source Type: research

Persistent and non-persistent strains of Listeria monocytogenes: A focus on growth kinetics under different temperature, salt, and pH conditions and their sensitivity to sanitizers.
This study aimed to investigate the effect of different conditions, including temperature (37 °C, 22 °C, and 4 °C), NaCl concentrations (2.5%, 4%, and 8%), and acidity (pH = 5), on the growth response of persistent and non-persistent isolates of Listeria monocytogenes. The resistance to two common sanitizers (benzalkonium chloride and hydrogen peroxide) was also investigated. A selected group of 41 persistent and non-persistent L. monocytogenes isolates recovered from three cheese processing plants during a previous longitudinal study was assembled. Average lag time was similar for pers...
Source: Food Microbiology - April 9, 2016 Category: Food Science Authors: Magalhães R, Ferreira V, Brandão TR, Palencia RC, Almeida G, Teixeira P Tags: Food Microbiol Source Type: research

Development of a HOG-based real-time PCR method to detect stress response changes in mycotoxigenic moulds.
rdoba JJ, Magan N Abstract There is a need to understand the mechanism of adaptation of toxigenic fungal species which are able to colonise highly specialised foods such as cured meats where there is a high osmotic stress due to the presence up to 20-22% NaCl during the ripening process. A new tool able to detect changes in stress related genes would be useful to understand the ecological reasons for the ability of these species to grow in specialised niches. In this work a real-time PCR (qPCR) using SYBR Green was developed. Primers were designed from the Hog1 gene involved in osmo-adaptation in fungi. For this, ...
Source: Food Microbiology - April 9, 2016 Category: Food Science Authors: Rodríguez A, Medina Á, Córdoba JJ, Magan N Tags: Food Microbiol Source Type: research

Metagenomic analysis of a Mexican ripened cheese reveals a unique complex microbiota.
Abstract Cotija cheese is a Mexican handcrafted product made from raw cow milk whose ripening process occurs spontaneously and, presumably, it is influenced by environmental conditions. Its sensory characteristics and safety are probably the result of the balance between microbial populations and their metabolic capacity. In this work, we studied the dominance and richness of the bacteria in the Cotija cheese microbiome, as well as their metabolic potential by high-throughput sequencing. By the analysis of 16S ribosomal sequences, it was found that this metagenome is composed mainly of three dominant genera: Lacto...
Source: Food Microbiology - April 9, 2016 Category: Food Science Authors: Escobar-Zepeda A, Sanchez-Flores A, Quirasco Baruch M Tags: Food Microbiol Source Type: research

Antibiotic resistance of Vibrio parahaemolyticus and Vibrio vulnificus in various countries: A review.
This article reviewed the antibiotic resistance profile of V. parahaemolyticus and V. vulnificus in the United States and other countries including Italy, Brazil, Philippines, Malaysia, Thailand, China, India, Iran, South Africa and Australia. The awareness of antimicrobial resistance of these two pathogens is not as well documented as other foodborne bacterial pathogens. Vibrio spp. are usually susceptible to most antimicrobials of veterinary and human significance. However, many studies reported that V. vulnificus and V. parahaemolyticus showed multiple-antibiotic resistance due to misuse of antibioti...
Source: Food Microbiology - April 9, 2016 Category: Food Science Authors: Elmahdi S, DaSilva LV, Parveen S Tags: Food Microbiol Source Type: research

The impact of pulsed light on decontamination, quality, and bacterial attachment of fresh raspberries.
Abstract Raspberries have served as vehicles for transmission of foodborne pathogens through fecal-oral route and have resulted in 11 outbreaks in the United States from 1983 through 2013. However, because of its dedicated structures and perishability, water based sanitizer washing cannot be used for raspberry decontamination. As a non-thermal technique, pulsed light (PL) may have the potential to maintain both safety and quality of fresh raspberries. The first objective of our study was to investigate Salmonella and Escherichia coli O157:H7 inactivation efficacy of pulsed light (PL) on fresh raspberries during 10...
Source: Food Microbiology - April 9, 2016 Category: Food Science Authors: Xu W, Wu C Tags: Food Microbiol Source Type: research

Microbial and sensorial models for head-on and gutted (HOG) Atlantic Salmon (Salmo salar) stored from 0 to 15 °C.
Microbial and sensorial models for head-on and gutted (HOG) Atlantic Salmon (Salmo salar) stored from 0 to 15 °C. Food Microbiol. 2016 Aug;57:144-50 Authors: Churchill OJ, Fernandez-Piquer J, Powell SM, Tamplin ML Abstract Predictive models offer efficient means to manage the quality and safety of highly perishable seafood. Salmon is an increasingly popular seafood, and relies on well managed domestic and international supply chains to minimize growth of spoilage and pathogenic bacteria. While the literature describes predictive models for smoked and modified atmosphere packaged salmon, there...
Source: Food Microbiology - April 9, 2016 Category: Food Science Authors: Churchill OJ, Fernandez-Piquer J, Powell SM, Tamplin ML Tags: Food Microbiol Source Type: research

Terminal acidic shock inhibits sour beer bottle conditioning by Saccharomyces cerevisiae.
Abstract During beer fermentation, the brewer's yeast Saccharomyces cerevisiae experiences a variety of shifting growth conditions, culminating in a low-oxygen, low-nutrient, high-ethanol, acidic environment. In beers that are bottle conditioned (i.e., carbonated in the bottle by supplying yeast with a small amount of sugar to metabolize into CO2), the S. cerevisiae cells must overcome these stressors to perform the ultimate act in beer production. However, medium shock caused by any of these variables can slow, stall, or even kill the yeast, resulting in production delays and economic losses. Here, we describe a ...
Source: Food Microbiology - April 9, 2016 Category: Food Science Authors: Rogers CM, Veatch D, Covey A, Staton C, Bochman ML Tags: Food Microbiol Source Type: research

Evaluation of growth, metabolism and production of potentially bioactive components during fermentation of barley with Lactobacillus reuteri.
Abstract Eighteen bacterial isolates from millet, buckwheat and rye flour were identified as Lactobacillus reuteri. Genomic fingerprinting (rep-PCR) revealed that they represented five strains and phylogenetic analyses using multi locus sequence analysis (MLSA) showed that all clustered with strains of rodent origin. Two strains (SU12-3 and SU18-3) from different phylogenetic clades were used in fermentations of six varieties of barley, both untreated and heat-treated (with inactivated indigenous enzymes) flour. They were compared with two probiotic strains of human origin (DSM 17938 and ATCC PTA 6475), one previo...
Source: Food Microbiology - April 9, 2016 Category: Food Science Authors: Pallin A, Agback P, Jonsson H, Roos S Tags: Food Microbiol Source Type: research

Efficacy of UV-C irradiation for inactivation of food-borne pathogens on sliced cheese packaged with different types and thicknesses of plastic films.
In this study, the efficacy of using UV-C light to inactivate sliced cheese inoculated with Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes and, packaged with 0.07 mm films of polyethylene terephthalate (PET), polyvinylchloride (PVC), polypropylene (PP), and polyethylene (PE) was investigated. The results show that compared with PET and PVC, PP and PE films showed significantly reduced levels of the three pathogens compared to inoculated but non-treated controls. Therefore, PP and PE films of different thicknesses (0.07 mm, 0.10 mm, and 0.13 mm) were then evaluated for patho...
Source: Food Microbiology - April 9, 2016 Category: Food Science Authors: Ha JW, Back KH, Kim YH, Kang DH Tags: Food Microbiol Source Type: research

Phenolic acid degradation potential and growth behavior of lactic acid bacteria in sunflower substrates.
In this study, growth behavior and degradation ability of chlorogenic acid of four lactic acid bacteria were explored. Data suggested that significant higher fermentation performances on sunflower flour as compared to sunflower protein concentrate were reached by Lactobacillus plantarum, Pediococcus pentosaceus, Lactobacillus gasseri and Bifidobacterium animalis subsp. lactis. In fermentation with the latter two strains reduced amounts of chlorogenic acid were observed in sunflower flour (-11.4% and -19.8%, respectively), which were more pronounced in the protein concentrate (-50.7% and -95.6%, respectively). Hig...
Source: Food Microbiology - April 9, 2016 Category: Food Science Authors: Fritsch C, Heinrich V, Vogel RF, Toelstede S Tags: Food Microbiol Source Type: research

Technological properties of Lactobacillus plantarum strains isolated from grape must fermentation.
In this study, we have carried out an integrated (molecular, technological, and biotechnological) characterization of L. plantarum strains isolated from Apulian wines in order to combine the two protechnological features (MLF performances and must acidification aptitudes). Several parameters such as sugar, pH and ethanol tolerance, resistance to lyophilisation and behaviour in grape must were evaluated. Moreover, the expression of stress gene markers was investigated and was linked to the ability of L. plantarum strains to grow and perform MLF. Co-inoculation of Saccharomyces cerevisiae and L. plantarum in grape ...
Source: Food Microbiology - April 9, 2016 Category: Food Science Authors: Berbegal C, Peña N, Russo P, Grieco F, Pardo I, Ferrer S, Spano G, Capozzi V Tags: Food Microbiol Source Type: research

Evaluation of corn oil as an additive in the pre-enrichment step to increase recovery of Salmonella enterica from oregano.
This study evaluated the effectiveness of corn oil as a component of the pre-enrichment broth to counteract antimicrobial compounds properties and increase the recovery of Salmonella from spices. Oregano samples artificially contaminated with Salmonella enterica were pre-enriched in modified Buffered Peptone Water (mBPW) supplemented with and without 2% (vol/vol) corn oil respectively. Samples were incubated overnight at 37 °C. The results showed that recovery of Salmonella from oregano samples was increased by ≥50% when pre-enriched with corn oil. Serovars were confirmed using a PCR serotyping method. In addit...
Source: Food Microbiology - April 9, 2016 Category: Food Science Authors: Jean-Gilles Beaubrun J, Flamer ML, Addy N, Ewing L, Gopinath G, Jarvis K, Grim C, Hanes DE Tags: Food Microbiol Source Type: research

Use of sourdough made with quinoa (Chenopodium quinoa) flour and autochthonous selected lactic acid bacteria for enhancing the nutritional, textural and sensory features of white bread.
This study exploited the potential of quinoa flour through sourdough fermentation. A number of advantages encouraged the manufacture of novel and healthy leavened baked goods. PMID: 26919812 [PubMed - in process] (Source: Food Microbiology)
Source: Food Microbiology - February 28, 2016 Category: Food Science Authors: Rizzello CG, Lorusso A, Montemurro M, Gobbetti M Tags: Food Microbiol Source Type: research

Optimization of heat and relative humidity conditions to reduce Escherichia coli O157:H7 contamination and maximize the germination of radish seeds.
Abstract We previously reported that a combination of heat and relative humidity (RH) had a marked bactericidal effect on Escherichia coli O157:H7 on radish seeds. Here, response surface methodology with a Box-Behnken design was used to build a model to predict reductions in E. coli O157:H7 populations based on three independent variables: heating temperature (55 °C, 60 °C, or 65 °C), RH (40%, 60%, and 80%), and holding time (8, 15, or 22 h). Optimum treatment conditions were selected using a desirability function. The predictive model for microbial reduction had a high regress...
Source: Food Microbiology - February 28, 2016 Category: Food Science Authors: Song MK, Kim HW, Rhee MS Tags: Food Microbiol Source Type: research

Culture dependent and independent genomic identification of Alicyclobacillus species in contaminated commercial fruit juices.
In this study, Alicyclobacillus contamination of commercial fruit juices in West Africa was investigated using culture-dependent and -independent approaches. Firstly, a total of 225 fruit juice products from Ghana (n = 39) and Nigeria (n = 186) were enriched with yeast-starch-glucose (YSG) broth (pH 3.7) following heat shock at 80 °C for 10 min. Alicyclobacillus was detected in 11.6% (26) of samples. Isolates were identified to the genus taxonomic level by genus-specific PCR which targeted the squalene-hopene-cyclase (shc) gene followed by analysis of the almost-complete 16S ribosomal RNA ...
Source: Food Microbiology - February 28, 2016 Category: Food Science Authors: Osopale BA, Witthuhn CR, Albertyn J, Oguntoyinbo FA Tags: Food Microbiol Source Type: research

Microbiological quality of fresh produce obtained from retail stores on the Eastern Shore of Maryland, United States of America.
Abstract The aim of this study was to investigate the microbiological quality of six types of fresh produce obtained from three retail stores located on the Eastern Shore of Maryland, USA. A total of 414 samples representing basil, cilantro, lettuce, scallion, spinach, and parsley were analyzed for total aerobic bacteria (APC), total coliforms, Escherichia coli, and three pathogenic bacteria (E. coli O157:H7, Listeria monocytogenes, and Salmonella), using standard methods. Presumptive pathogenic isolates were confirmed using BAX Polymerase Chain Reaction. Total aerobic populations varied widely between sample...
Source: Food Microbiology - February 28, 2016 Category: Food Science Authors: Korir RC, Parveen S, Hashem F, Bowers J Tags: Food Microbiol Source Type: research

Biofilm formation on Conservolea natural black olives during single and combined inoculation with a functional Lactobacillus pentosus starter culture.
Abstract The potential of biofilm formation of multifunctional starters Lactobacillus pentosus B281 and Pichia membranifaciens M3A during inoculated fermentation of Conservolea natural black olives according to Greek-style processing was investigated. Olives were directly brined in 8% (w/v) NaCl following three fermentation procedures namely, i) spontaneous fermentation, ii) inoculated fermentation with L. pentosus B281, and iii) co-inoculated fermentation with L. pentosus B281 and P. membranifaciens M3A. Lactic acid bacteria (LAB) and yeasts were monitored on olives by plate counting for a period o...
Source: Food Microbiology - February 28, 2016 Category: Food Science Authors: Grounta A, Doulgeraki AI, Nychas GJ, Panagou EZ Tags: Food Microbiol Source Type: research

Torulaspora delbrueckii in the brewing process: A new approach to enhance bioflavour and to reduce ethanol content.
Abstract Nowadays, consumers require fermented alcoholic beverages with particular and enhanced flavour profiles while avoiding the health concerns due to high ethanol content. Here, the use of Torulaspora delbrueckii was evaluated for beer production, in both pure and in mixed cultures with a Saccharomyces cerevisiae starter strain (US-05). The yeast interactions were also evaluated. In mixed fermentations with S. cerevisiae, the main analytical characters from T. delbrueckii were comparable with those of the S. cerevisiae starter strain, but the beers were characterized by a distinctive overall an...
Source: Food Microbiology - February 28, 2016 Category: Food Science Authors: Canonico L, Agarbati A, Comitini F, Ciani M Tags: Food Microbiol Source Type: research

Suitability of a new mixed-strain starter for manufacturing uncooked raw ewe's milk cheeses.
ier F Abstract Most raw milk Ossau-Iraty cheeses are currently manufactured on-farm using the same commercial streptococcal-lactococcal starter (S1). One way to enhance the microbial diversity that gives raw milk its advantages for cheese-making is to formulate new starters combining diverse, characterized strains. A new starter (OI) combining 6 raw milk strains of lactococci, recently isolated and characterized, was tested in parallel with the current starter by making 12 Ossau-Iraty raw milk cheeses at 3 farmhouses under the conditions prevailing at each farm. Compliance of the sensory characteristics with those...
Source: Food Microbiology - February 28, 2016 Category: Food Science Authors: Feutry F, Torre P, Arana I, Garcia S, Pérez Elortondo FJ, Berthier F Tags: Food Microbiol Source Type: research

Effect of temperature, pH, and water activity on Mucor spp. growth on synthetic medium, cheese analog and cheese.
This study offers a relevant predictive model of growth that may be used for better cheese production control but also raises the question of adaptation of some Mucor strains to the cheese. PMID: 26919819 [PubMed - in process] (Source: Food Microbiology)
Source: Food Microbiology - February 28, 2016 Category: Food Science Authors: Morin-Sardin S, Rigalma K, Coroller L, Jany JL, Coton E Tags: Food Microbiol Source Type: research

Inactivation of murine norovirus-1 in the edible seaweeds Capsosiphon fulvescens and Hizikia fusiforme using gamma radiation.
This study investigated the effects of gamma radiation (3-10 kGy) upon the inactivation of murine norovirus-1 (MNV-1), a human norovirus (NoV) surrogate. The edible green and brown algae, fulvescens (Capsosiphon fulvescens) and fusiforme (Hizikia fusiforme), respectively, were experimentally contaminated with 5-6 log10 plaque forming units (PFU)/ml MNV-1. The titer of MNV-1 significantly decreased (P  0.05) different in both algae following gamma radiation. The Weibull model was used to generate non-linear survival curves and to calculate Gd values for 1, 2, and 3 log10 reductions of MNV-1 in fulvescens (R(2...
Source: Food Microbiology - February 28, 2016 Category: Food Science Authors: Park SY, Kang S, Ha SD Tags: Food Microbiol Source Type: research

Die another day: Fate of heat-treated Geobacillus stearothermophilus ATCC 12980 spores during storage under growth-preventing conditions.
ert O Abstract Geobacillus stearothermophilus spores are recognized as one of the most wet-heat resistant among aerobic spore-forming bacteria and are responsible for 35% of canned food spoilage after incubation at 55 °C. The purpose of this study was to investigate and model the fate of heat-treated survivor spores of G. stearothermophilus ATCC 12980 in growth-preventing environment. G. stearothermophilus spores were heat-treated at four different conditions to reach one or two decimal reductions. Heat-treated spores were stored in nutrient broth at different temperatures and pH under growth-pr...
Source: Food Microbiology - February 28, 2016 Category: Food Science Authors: Mtimet N, Trunet C, Mathot AG, Venaille L, Leguérinel I, Coroller L, Couvert O Tags: Food Microbiol Source Type: research

Survival of Penicillium spp. conidia during deep-frying and baking steps of frozen chicken nuggets processing.
This study aimed at determining whether Penicillium spp. strains could survive through the heat treatment applied during the processing of frozen chicken nuggets. Firstly, it was found that the conidia of Penicillium were not able to survive the heat shock in phosphate buffer at pH 7.2 in thermal death tubes (TDT) at 80 °C/30 min. Subsequently, each Penicillium strain was inoculated in frozen chicken nuggets, which were subjected to the following treatments: i) only deep frying (frying oil at 195-200 °C), ii) only baking (120-130 °C until the internal temperature reached 70 °C) and ...
Source: Food Microbiology - January 16, 2016 Category: Food Science Authors: Wigmann ÉF, Moreira RC, Alvarenga VO, Sant'Ana AS, Copetti MV Tags: Food Microbiol Source Type: research

Expression of Listeria monocytogenes key virulence genes during growth in liquid medium, on rocket and melon at 4, 10 and 30 °C.
Expression of Listeria monocytogenes key virulence genes during growth in liquid medium, on rocket and melon at 4, 10 and 30 °C. Food Microbiol. 2016 May;55:7-15 Authors: Hadjilouka A, Molfeta C, Panagiotopoulou O, Paramithiotis S, Mataragas M, Drosinos EH Abstract The aim of the present study was to assess the expression of key virulence genes, during growth of a Listeria monocytogenes isolate in liquid medium, on melon and rocket at different temperatures and time. For that purpose, BHI broth, rocket and melon were inoculated at 7.0-7.5 log CFU mL(-1) or g(-1)and stored at 4, 10 and 30 ...
Source: Food Microbiology - January 16, 2016 Category: Food Science Authors: Hadjilouka A, Molfeta C, Panagiotopoulou O, Paramithiotis S, Mataragas M, Drosinos EH Tags: Food Microbiol Source Type: research

Application and validation of autochthonous Lactobacillus plantarum starter cultures for controlled malolactic fermentation and its influence on the aromatic profile of cherry wines.
Abstract Lactic acid bacteria (LAB) used for malolactic fermentation (MLF) has a great effect on the production and quality of cherry wines. The present study used an autochthonous Lb. plantarum strain of SGJ-24 which was isolated from spontaneous MLF cherry wines and selected by its best MLF performance and tolerance, to investigate its effect on the kinetic of vinification and on chemical and volatile characteristics of Rainer and May Duck cherry wines, in comparison with a commercial Oenococcus oeni strain of 31 MBR. Monitoring of MLF was carried out by measuring cell viability and malic acid metabolism, a...
Source: Food Microbiology - January 16, 2016 Category: Food Science Authors: Sun SY, Gong HS, Liu WL, Jin CW Tags: Food Microbiol Source Type: research

Development of a predictive model for the growth kinetics of aerobic microbial population on pomegranate marinated chicken breast fillets under isothermal and dynamic temperature conditions.
Abstract The aim of this study was the development of a model to describe the growth kinetics of aerobic microbial population of chicken breast fillets marinated in pomegranate juice under isothermal and dynamic temperature conditions. Moreover, the effect of pomegranate juice on the extension of the shelf life of the product was investigated. Samples (10 g) of chicken breast fillets were immersed in marinades containing pomegranate juice for 3 h at 4 °C following storage under aerobic conditions at 4, 10, and 15 °C for 10 days. Total Viable Counts (TVC), Pseudomonas spp and lactic acid...
Source: Food Microbiology - January 16, 2016 Category: Food Science Authors: Lytou A, Panagou EZ, Nychas GJ Tags: Food Microbiol Source Type: research

Exploring the phenotypic space of non-Saccharomyces wine yeast biodiversity.
Abstract Tremendous microbial diversity exists in vineyards, and the potential to harness this diversity for novel mixed or pure starter cultures for wine fermentation has received significant attention in recent years. However, most studies are limited to a small subset of strains and species. Here we present data from a systematic screen of 91 yeast isolates from South African grape must and vineyard samples for oenologically relevant traits. One focus area was finding non-Saccharomyces isolates showing both reduced ethanol yields, as well as improved aromatic characteristics. Of the 91 isolates evaluated initia...
Source: Food Microbiology - January 16, 2016 Category: Food Science Authors: Rossouw D, Bauer FF Tags: Food Microbiol Source Type: research

Effect of sanitizer combined with steam heating on the inactivation of foodborne pathogens in a biofilm on stainless steel.
Abstract The combined effect of chemical sanitizers including sodium hypochlorite, hydrogen peroxide, iodophor, and benzalkonium chloride with steam heating on the inactivation of biofilms formed by Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes on stainless steel was investigated. Six day old biofilms, comprised of a mixture of three strains each of three foodborne pathogens, were produced on stainless steel coupons at 25 °C and treated with each sanitizer alone (for 5, 15, and 30 s), steam alone (for 5, 10, and 20 s), and the combination. There was a synergistic e...
Source: Food Microbiology - January 16, 2016 Category: Food Science Authors: Ban GH, Kang DH Tags: Food Microbiol Source Type: research

Abundance, diversity and community composition of free-living protozoa on vegetable sprouts.
Abstract Interactions with free-living protozoa (FLP) have been implicated in the persistence of pathogenic bacteria on food products. In order to assess the potential involvement of FLP in this contamination, detailed knowledge on their occurrence, abundance and diversity on food products is required. In the present study, enrichment and cultivation methods were used to inventory and quantify FLP on eight types of commercial vegetable sprouts (alfalfa, beetroot, cress, green pea, leek, mung bean, red cabbage and rosabi). In parallel, total aerobic bacteria and Escherichia coli counts were performed. The vegetable...
Source: Food Microbiology - January 16, 2016 Category: Food Science Authors: Chavatte N, Lambrecht E, Van Damme I, Sabbe K, Houf K Tags: Food Microbiol Source Type: research

Effect of pH on Thermoanaerobacterium thermosaccharolyticum DSM 571 growth, spore heat resistance and recovery.
, Couvert O Abstract Thermophilic spore-forming bacteria are potential contaminants in several industrial sectors involving high temperatures (40-65 °C) in the manufacturing process. Among those thermophilic spore-forming bacteria, Thermoanaerobacterium thermosaccharolyticum, called "the swelling canned food spoiler", has generated interest over the last decade in the food sector. The aim of this study was to investigate and to model pH effect on growth, heat resistance and recovery abilities after a heat-treatment of T. thermosaccharolyticum DSM 571. Growth and sporulation were conducted o...
Source: Food Microbiology - January 16, 2016 Category: Food Science Authors: Mtimet N, Guégan S, Durand L, Mathot AG, Venaille L, Leguérinel I, Coroller L, Couvert O Tags: Food Microbiol Source Type: research

Transcriptome analysis of Bacillus thuringiensis spore life, germination and cell outgrowth in a vegetable-based food model.
Abstract Toxigenic species belonging to Bacillus cereus sensu lato, including Bacillus thuringiensis, cause foodborne outbreaks thanks to their capacity to survive as spores and to grow in food matrixes. The goal of this work was to assess by means of a genome-wide transcriptional assay, in the food isolate B. thuringiensis UC10070, the gene expression behind the process of spore germination and consequent outgrowth in a vegetable-based food model. Scanning electron microscopy and Energy Dispersive X-ray microanalysis were applied to select the key steps of B. thuringiensis UC10070 cell cycle to be analyzed w...
Source: Food Microbiology - January 16, 2016 Category: Food Science Authors: Bassi D, Colla F, Gazzola S, Puglisi E, Delledonne M, Cocconcelli PS Tags: Food Microbiol Source Type: research

Novel method based on chromogenic media for discrimination and selective enumeration of lactic acid bacteria in fermented milk products.
aux C Abstract Microbial analyses of fermented milk products require selective methods to discriminate between close species simultaneously present in high amounts. A culture-based method combining novel chromogenic agar media and appropriate incubation conditions was developed to enumerate lactic acid bacteria (LAB) strains in fermented milk. M1 agar, containing two chromogenic substrates, allowed selective enumeration of Lactobacillus rhamnosus, two strains of Lactobacillus paracasei subsp. paracasei and Streptococcus salivarius subsp. thermophilus based on differential β-galactosidase and β-glucosidas...
Source: Food Microbiology - January 16, 2016 Category: Food Science Authors: Galat A, Dufresne J, Combrisson J, Thépaut J, Boumghar-Bourtchai L, Boyer M, Fourmestraux C Tags: Food Microbiol Source Type: research

Survival mechanism of Escherichia coli O157:H7 against combined treatment with acetic acid and sodium chloride.
Abstract The combination of salt and acid is commonly used in the production of many foods, including pickles and fermented foods. However, in our previous studies, the addition of salt significantly reduced the inhibitory effect of acetic acid on Escherichia coli O157:H7 in laboratory media and pickled cucumbers. Therefore, this study was conducted to determine the mechanism by which salt confers resistance against acetic acid in E. coli O157:H7. The addition of high concentrations (up to 9% or 15% [w/v]) of salt increased the resistance of E. coli O157:H7 to acetic acid treatment. Combined treatment with ac...
Source: Food Microbiology - January 16, 2016 Category: Food Science Authors: Lee SY, Kang DH Tags: Food Microbiol Source Type: research

Use of a novel medium, the Polymyxin Ceftazidime Oxford Medium, for isolation of Listeria monocytogenes from raw or non-pasteurized foods.
nas C, Gutiérrez-González P, Castillo A Abstract Polymyxin Ceftazidime Oxford Medium (PCOM), a novel selective and differential plating medium for Listeria monocytogenes was compared with Modified Oxford Agar (MOX) for efficacy to isolate L. monocytogenes and other Listeria spp. naturally present in non-pasteurized Mexican-style cheese (n = 50), non-pasteurized fresh squeezed orange juice (n = 50), raw beef chunks (n = 36), and fresh cabbage (n = 125). Samples were collected from retail markets and farms in Mexico and tested following the US Department of ...
Source: Food Microbiology - January 16, 2016 Category: Food Science Authors: Martínez-Gonzáles NE, Martínez-Chávez L, Cabrera-Díaz E, Martínez-Cárdenas C, Gutiérrez-González P, Castillo A Tags: Food Microbiol Source Type: research

Metaproteomics and ultrastructure characterization of Komagataeibacter spp. involved in high-acid spirit vinegar production.
X, Barja F Abstract Acetic acid bacteria (AAB) are widespread microorganisms in nature, extensively used in food industry to transform alcohols and sugar alcohols into their corresponding organic acids. Specialized strains are used in the production of vinegar through the oxidative transformation of ethanol into acetic acid. The main AAB involved in the production of high-acid vinegars using the submerged fermentation method belong to the genus Komagataeibacter, characterized by their higher ADH stability and activity, and higher acetic acid resistance (15-20%), compared to other AAB. In this work, the bacteria i...
Source: Food Microbiology - January 16, 2016 Category: Food Science Authors: Andrés-Barrao C, Saad MM, Cabello Ferrete E, Bravo D, Chappuis ML, Ortega Pérez R, Junier P, Perret X, Barja F Tags: Food Microbiol Source Type: research