Fermentation of fruit juices by the osmotolerant yeast Candida magnoliae

This study focuses on the assessment of the fermentation conditions required to modulate the metabolic flux in the osmotolerant yeast Candida magnoliae and evaluate its potential to produce low-alcoholic and low-caloric fermented beverages. For that purpose, two strains, PYCC 2903 and PYCC 3191, were used and fermentation conditions as oxygenation, sugar concentration and the ratio of glucose to fructose were studied using synthetic culture media. Candida magnoliae PYCC 2903 was subsequently used to ferment real industrial fructose-rich substrates such as fruit juices. Sugar consumption profiles for C.magnoliae PYCC 2903 incubated aerobically in the presence of high fructose and glucose concentrations (15%, 10% and 5%) showed a selective utilization of fructose, denoting a preference for this sugar over glucose. The lower ratio between ethanol and sugar alcohols yield was obtained for both strains incubated under oxygen limitation simulating industrial fructose-rich substrates, confirming the ability of this yeast to direct fermentation towards alternative products. Enzymatic assays for hexokinase activity in terms of capacity and affinity for glucose and fructose were performed, aiming to elucidate its contribution to the fructophilic behaviour of this yeast. Enzymatic assays for both strains showed that the Vmax is two to threefold higher for fructose than for glucose but Km is also 10-20-fold higher for this sugar than for glucose. Hence, hexokinase kinetic properties do not explain fructophily in C.magnoliae. This indicates that fructose transport is probably determining in this respect, as observed for other fructophilic yeasts. Fruit juice fermentations with C.magnoliae PYCC 2903 revealed a potential for the production of beverages with interesting sensorial properties. Pear and peach fermentations exhibited the best results with the lowest ratio between ethanol and sugar alcohols yield and the most pleasant organoleptic features.

Molecular characterization of Salmonella strains in individuals with acute diarrhea syndrome in the State of Sucre, Venezuela

INTRODUCTION:In Venezuela, acute diarrheic syndrome (ADS) is a primary cause of morbi-mortality, often involving the Salmonella genus. Salmonella infections are associated with acute gastroenteritis, one of the most common alimentary intoxications, and caused by the consumption of contaminated water and food, especially meat. METHODS: Conventional and molecular methods were used to detect Salmonella strains from 330 fecal samples from individuals of different ages and both sexes with ADS. Polymerase chain reaction (PCR) was used for the molecular characterization of Salmonella, using invA, sefA, and fliC genes for the identification of this genus and the serotypes Enteritidis and Typhimurium, respectively. RESULTS: The highest frequency of individuals with ADS was found in children 0-2 years old (39.4%), and the overall frequency of positive coprocultures was 76.9%. A total of 14 (4.2%) strains were biochemically and immunologically identified as Salmonella enterica subsp. enterica, of which 7 were classified as belonging to the Enteritidis serotype, 4 to the Typhimurium serotype, and 3 to other serotypes. The S. enterica strains were distributed more frequently in the age groups 3-4 and 9-10 years old. CONCLUSIONS: The molecular characterization method used proved to be highly specific for the typing of S. enterica strains using DNA extracted from both the isolated colonies and selective enrichment broths directly inoculated with fecal samples, thus representing a complementary tool for the detection and identification of ADS-causing bacteria.

Prevalence of enterotoxin-encoding genes and antimicrobial resistance in coagulase-negative and coagulase-positive Staphylococcus isolates from black pudding

INTRODUCTION: Staphylococcal species are pathogens that are responsible for outbreaks of foodborne diseases. The aim of this study was to investigate the prevalence of enterotoxin-genes and the antimicrobial resistance profile in staphylococcus coagulase-negative (CoNS) and coagulasepositive (CoPS) isolates from black pudding in southern Brazil. METHODS: Two hundred typical and atypical colonies from Baird-Parker agar were inoculated on mannitol salt agar. Eighty-two mannitol-positive staphylococci were submitted to conventional biochemical tests and antimicrobial susceptibility profiling. The presence of coagulase (coa) and enterotoxin (se) genes was investigated by polymerase chain reaction. RESULTS: The isolates were divided into 2 groups: 75.6% (62/82) were CoNS and 24.4% (20/82) were CoPS. The biochemical tests identified 9 species, of which Staphylococcus saprophyticus (37.8%) and Staphylococcus carnosus (15.9%) were the most prevalent. Antimicrobial susceptibility tests showed resistance phenotypes to antibiotics widely administered in humans, such as gentamicin, tetracycline, chloramphenicol, and erythromycin. The coa gene was detected in 19.5% (16/82) of the strains and 4 polymorphic DNA fragments were observed. Five CoNS isolates carrying the coa gene were submitted for 16S rRNA sequencing and 3 showed similarity with CoNS. Forty strains were positive for at least 1 enterotoxin-encoding gene, the genes most frequently detected were sea (28.6%) and seb (27.5%). CONCLUSIONS: The presence of antimicrobial resistant and enterotoxin-encoding genes in staphylococci isolates from black pudding indicated that this fermented food may represent a potential health risk, since staphylococci present in food could cause foodborne diseases or be a possible route for the transfer of antimicrobial resistance to humans.

Approaches towards tick and tick-borne diseases control

Ticks are obligate haematophagous ectoparasites of wild and domestic animals as well as humans, considered to be second worldwide to mosquitoes as vectors of human diseases. Tick-borne diseases are responsible worldwide for great economic losses in terms of mortality and morbidity of livestock animals. This review concerns to the different tick and tick-parasites control methods having a major focus on vaccines. Control of tick infestations has been mainly based on the use of acaricides, a control measure with serious drawbacks, as responsible for the contamination of milk and meat products, as a selective factor for acaricide-resistant ticks and as an environmental contaminant. Research on alternatives to the use of acaricides is strongly represented by tick vaccines considered a more cost-effective and environmentally safe strategy. Vaccines based on the Bm86 tick antigen were used in the first commercially available cattle tick vaccines and showed good results in reducing tick numbers, affecting weight and reproductive performance of female ticks which resulted in reduction of cattle tick populations over time and consequently lower reduction of the pathogen agents they carry.

Epidemiological factors associated with seropositivity for toxoplasmosis in pregnant women from Gurupi, State of Tocantins, Brazil

Introduction Knowledge of the prevalence and risk factors for Toxoplasma gondii dissemination among pregnant women is relevant because the parasite can be spread from mother to infant. The objective of this study was to assess the epidemiology and risk factors of toxoplasmosis in pregnant women from Gurupi, State of Tocantins, Brazil, from February 2012 to June 2013. Methods The study population included 487 pregnant women. Sociodemographic, dietary and cultural data were collected using a standardized and validated form. Peripheral blood was collected for serologic testing using the ELISA test (IgM/IgG antibodies). The data were analyzed by comparing seropositivity with risk factors using crude and adjusted odds ratios. Results The prevalence rate for IgG and IgM antibodies was 68.7% and 5.7%, respectively. Sociodemographic characteristics associated with toxoplasmosis risk included the following: education level ≤ 8 years (OR: 6.612; CI: 1.450-30.144), age ≥ 30 years (OR: 5.273; CI: 1.166-23.844), working outside the home (OR: 1.604; CI: 1.015-2.536), and family income of two minimum wages or lower (OR: 2.700; CI: 1.891-8.182). Regarding dietary habits, there was a significant association of seropositivity with meat intake (OR: 1.78; CI: 1.149-4.080), cutting vegetables without washing the cutting board beforehand (OR: 2.051; CI: 1.165-3.614), frequent intake of vegetables (OR: 2.051; CI: 1.368-3.006) and in natura milk intake (OR: 2.422; CI: 1.014-5.785). Conclusions The high prevalence rates of toxoplasmosis in Gurupi are related to age, raw meat and in natura milk intake, as well as education level, working outside the home, and poor hygienic habits during meal preparation.

Toxoplasma gondii infection: seroprevalence and associated risk factors among primary schoolchildren in Lagos City, Southern Nigeria

INTRODUCTION: Toxoplasma gondii infection has been described as the most widespread zoonotic infection of humans and other animals. Information concerning T. gondii infection among schoolchildren is unavailable in Lagos City, Nigeria. METHODS: This cross-sectional study investigated the seroprevalence and risk factors associated with T. gondii infection among primary schoolchildren (PSC) from a community located in the center of Lagos, southern Nigeria, from November 2013 to March 2014. A total of 382 PSC were screened for the presence of sera anti-T. gondii antibodies using a latex agglutination test (TOXO Test-MT, Tokyo, Japan). A cutoff titer of ≥ 1:32 was considered positive, while titers ≥ 1:1,024 indicated high responders. Questionnaires were also used to obtain data on possible risk factors from parents/guardians. RESULTS: The overall seroprevalence was 24% (91/382), and 83.5% (76/91) of seropositive PSC were classified as high responders. Among the risk factors tested, including contact with cats and soil, consumption of raw meat and vegetables, and drinking unboiled water, none showed statistical significance after multivariate adjustment. No associations were observed among age, gender, body mass index (BMI), and parents' occupation/educational level. CONCLUSIONS: The findings in this study show evidence of active infection, and hence, there is need for urgent preventive measures in this city. Further investigation is required to clarify the transmission routes. Policy makers also need to initiate prevention and control programs to protect pregnant women and immunocompromised patients in particular because they are more severely affected by T. gondii infection.

Risk factors for Toxoplasma gondii infection among pregnant women from the State of Tocantins, Northern Brazil

ABSTRACT INTRODUCTION: The prevalence of infection by Toxoplasma gondii and associated risk factors in pregnant women in Tocantins, Northern Brazil were assessed. METHODS: Serological analysis was performed in 338 serum samples and an oral questionnaire was utilized to identify potential risk factors. RESULTS: Anti-IgG antibodies against T. gondii were detected in 71% (240/338) of the pregnant women. Prior contact with cats and meat handling were found to be associated with T. gondii infection. CONCLUSIONS: A considerable percentage (29%) of women living in the Tocantins area remain susceptible to infection by the T. gondii protozoon, representing a serious public health risk.

Polyhydroxyalkanoates production by photosynthetic mixed cultures

Polyhydroxyalkanoates (PHAs) are natural biologically synthesized polymers that have been the subject of much interest in the last decades due to their biodegradability. Thus far, its microbial production is associated with high operational costs, which increases PHA prices and limits its marketability. To address this situation, this thesis’ work proposes the utilization of photosynthetic mixed cultures (PMC) as a new PHA production system that may lead to a reduction in operational costs. In fact, the operational strategies developed in this work led to the selection of PHA accumulating PMCs that, unlike the traditional mixed microbial cultures, do not require aeration, thus permitting savings in this significant operational cost. In particular, the first PHA accumulating PMC tested in this work was selected under non-aerated illuminated conditions in a feast and famine regime, being obtained a consortium of bacteria and algae, where photosynthetic bacteria accumulated PHA during the feast phase and consumed it for growth during the famine phase, using the oxygen produced by algae. In this symbiotic system, a maximum PHA content of 20% cell dry weight (cdw) was reached, proving for the first time, the capacity of a PMC to accumulate PHA. During adaptation to dark/light alternating conditions, the culture decreased its algae content but maintained its viability, achieving a PHA content of 30% cdw. Also, the PMC was found to be able to utilize different volatile fatty acids for PHA production, accumulating up to 20% cdw of a PHA co-polymer composed of 3-hydroxybutyrate (3HB) and 3-hydroxyvalerate (HV) monomers. Finally, a new selective approach for the enrichment of PMCs in PHA accumulating bacteria was tested. Instead of imposing a feast and famine regime, a permanent feast regime was used, thus selecting a PMC that was capable of simultaneously growing and accumulating PHA, being attained a maximum PHA content of 60% cdw, the highest value reported for a PMC thus far. The results presented in this thesis prospect the utilization of cheap, VFA-rich fermented wastes as substrates for PHA production, which combined with this new photosynthetic technology opens up the possibility for direct sunlight illumination, leading to a more cost-effective and environmentally sustainable PHA production process.

Alcohol-dependent patients receiving specialised outpatient care: an overview of gender issues

OBJECTIVE: The objective of the present study, with focus on gender, was aimed at evaluating alcohol-dependent individual in terms of socio-demographic variables related to alcohol consumption and therapeutic interventions. METHODS: This is a retrospective cross-sectional study of 1,051 patients (833 men and 218 women), with diagnosis of alcohol dependence syndrome, according to ICD-10 criteria, who had sought treatment for the first time at a specialised health centre between 2000 and 2006. RESULTS: The results showed that women, compared to men, are more likely to be unemployed and without partner, in addition to having higher educational level, latter age of alcohol initiation, needing less outpatient alcohol detoxification program, consuming more fermented beverage, presenting less psychiatric comorbidities, and using less coadjutant medications during treatment. CONCLUSION: We can state that some peculiarities exist permeating both gender and alcohol consumption. A further focus on the characteristics of each population is needed to facilitate the adequate use of therapeutic interventions according to gender specificities.

New bio-strategies for ochratoxin A detoxification using lactic acid bacteria

The occurrence of mycotoxigenic moulds such as Aspergillus, Penicillium and Fusarium in food and feed has an important impact on public health, by the appearance of acute and chronic mycotoxicoses in humans and animals, which is more severe in the developing countries due to lack of food security, poverty and malnutrition. This mould contamination also constitutes a major economic problem due the lost of crop production. A great variety of filamentous fungi is able to produce highly toxic secondary metabolites known as mycotoxins. Most of the mycotoxins are carcinogenic, mutagenic, neurotoxic and immunosuppressive, being ochratoxin A (OTA) one of the most important. OTA is toxic to animals and humans, mainly due to its nephrotoxic properties. Several approaches have been developed for decontamination of mycotoxins in foods, such as, prevention of contamination, biodegradation of mycotoxins-containing food and feed with microorganisms or enzymes and inhibition or absorption of mycotoxin content of consumed food into the digestive tract. Some group of Gram-positive bacteria named lactic acid bacteria (LAB) are able to release some molecules that can influence the mould growth, improving the shelf life of many fermented products and reducing health risks due to exposure to mycotoxins. Some LAB are capable of mycotoxin detoxification. Recently our group was the first to describe the ability of LAB strains to biodegrade OTA, more specifically, Pediococcus parvulus strains isolated from Douro wines. The pathway of this biodegradation was identified previously in other microorganisms. OTA can be degraded through the hydrolysis of the amide bond that links the L-β-phenylalanine molecule to the ochratoxin alpha (OTα) a non toxic compound. It is known that some peptidases from different origins can mediate the hydrolysis reaction like, carboxypeptidase A an enzyme from the bovine pancreas, a commercial lipase and several commercial proteases. So, we wanted to have a better understanding of this OTA degradation process when LAB are involved and identify which molecules where present in this process. For achieving our aim we used some bioinformatics tools (BLAST, CLUSTALX2, CLC Sequence Viewer 7, Finch TV). We also designed specific primers and realized gene specific PCR. The template DNA used came from LAB strains samples of our previous work, and other DNA LAB strains isolated from elderberry fruit, silage, milk and sausages. Through the employment of bioinformatics tools it was possible to identify several proteins belonging to the carboxypeptidase family that participate in the process of OTA degradation, such as serine type D-Ala-D-Ala carboxypeptidase and membrane carboxypeptidase. In conclusions, this work has identified carboxypeptidase proteins being one of the molecules present in the OTA degradation process when LAB are involved.

Novas bio-estratégias para a destoxificação de ocratoxina A utilizando bactérias do ácido láctico

A ocorrência de bolores micotoxigénicos pertencentes aos géneros Aspergillus, Penicillium e Fusarium em alimentos para consumo Humano e animal, tem um impacto importante sobre a saúde pública e constitui também um importante problema económico. Isto é devido à síntese por este tipo de fungos filamentosos de metabolitos altamente tóxicos conhecidos como micotoxinas. A maioria das micotoxinas são substâncias cancerígenas, mutagénicas, neurotóxicas e imunossupressoras, sendo a ocratoxina A (OTA) uma das mais importantes. A OTA é uma micotoxina, tóxica para os animais e Humanos principalmente devido às suas propriedades nefrotóxicas. Alguns grupos de bactérias gram positivas nomeadamente as bactérias do ácido láctico (BAL) são capazes de controlar o crescimento de fungos, melhorando e aumentando a vida útil de muitos produtos fermentados e, assim, reduzir os riscos para a saúde provocados pela exposição às micotoxinas. Algumas BAL são, também, capazes de destoxificar certas micotoxinas. Em trabalhos anteriores do nosso grupo foi observada a biodegradação da OTA por estirpes de Pediococcus parvulus isoladas de vinhos do Douro. Assim, com este trabalho, pretendeu-se compreender com maior detalhe o processo de biodegradação da OTA pelas referidas estirpes e identificar quais as enzimas que estão associadas à sua biodegradação. Para atingir este objetivo utilizaram-se algumas ferramentas ioinformáticas (BLAST, CLUSTALX2, CLC Sequence Viewer 7, Finch TV), desenharam-se primers específicos e realizaram-se PCR específicos para os genes envolvidos. Através da utilização de ferramentas de bioinformática, foi possível identificar várias proteínas que pertencem à família das carboxipeptidases e que podem eventualmente participar no processo da degradação da OTA, tais como D-Ala-D-Ala carboxipeptidase serínica e carboxipeptidase membranar. Estas BAL podem desempenhar um papel importante na destoxificação da OTA, sendo as carboxipeptidases uma das enzimas envolvidas na sua biodegradação.

Aromatic amines sources, environmental impact and remediation

Aromatic amines are widely used industrial chemicals as their major sources in the environment include several chemical industry sectors such as oil refining, synthetic polymers, dyes, adhesives, rubbers, perfume, pharmaceuticals, pesticides and explosives. They result also from diesel exhaust, combustion of wood chips and rubber and tobacco smoke. Some types of aromatic amines are generated during cooking, special grilled meat and fish, as well. The intensive use and production of these compounds explains its occurrence in the environment such as in air, water and soil, thereby creating a potential for human exposure. Since aromatic amines are potential carcinogenic and toxic agents, they constitute an important class of environmental pollutants of enormous concern, which efficient removal is a crucial task for researchers, so several methods have been investigated and applied. In this chapter the types and general properties of aromatic amine compounds are reviewed. As aromatic amines are continuously entering the environment from various sources and have been designated as high priority pollutants, their presence in the environment must be monitored at concentration levels lower than 30 mg L1, compatible with the limits allowed by the regulations. Consequently, most relevant analytical methods to detect the aromatic amines composition in environmental matrices, and for monitoring their degradation, are essential and will be presented. Those include Spectroscopy, namely UV/visible and Fourier Transform Infrared Spectroscopy (FTIR); Chromatography, in particular Thin Layer (TLC), High Performance Liquid (HPLC) and Gas chromatography (GC); Capillary electrophoresis (CE); Mass spectrometry (MS) and combination of different methods including GC-MS, HPLC-MS and CE-MS. Choosing the best methods depend on their availability, costs, detection limit and sample concentration, which sometimes need to be concentrate or pretreated. However, combined methods may give more complete results based on the complementary information. The environmental impact, toxicity and carcinogenicity of many aromatic amines have been reported and are emphasized in this chapter too. Lately, the conventional aromatic amines degradation and the alternative biodegradation processes are highlighted. Parameters affecting biodegradation, role of different electron acceptors in aerobic and anaerobic biodegradation and kinetics are discussed. Conventional processes including extraction, adsorption onto activated carbon, chemical oxidation, advanced oxidation, electrochemical techniques and irradiation suffer from drawbacks including high costs, formation of hazardous by-products and low efficiency. Biological processes, taking advantage of the naturally processes occurring in environment, have been developed and tested, proved as an economic, energy efficient and environmentally feasible alternative. Aerobic biodegradation is one of the most promising techniques for aromatic amines remediation, but has the drawback of aromatic amines autooxidation once they are exposed to oxygen, instead of their degradation. Higher costs, especially due to power consumption for aeration, can also limit its application. Anaerobic degradation technology is the novel path for treatment of a wide variety of aromatic amines, including industrial wastewater, and will be discussed. However, some are difficult to degrade under anaerobic conditions and, thus, other electron acceptors such as nitrate, iron, sulphate, manganese and carbonate have, alternatively, been tested.

An overview of the brewing process

The first chapter of this book has an introductory character, which discusses the basics of brewing. This includes not only the essential ingredients of beer, but also the steps in the process that transforms the raw materials (grains, hops) into fermented and maturated beer. Special attention is given to the processes involving an organized action of enzymes, which convert the polymeric macromolecules present in malt (such as proteins and polysaccharides) into simple sugars and amino acids; making them available/assimilable for the yeast during fermentation.

Effects of fermentation residues on the melt processability and thermomechanical degradation of PHBV produced from cheese whey using mixed microbial cultures

"Available online 28 March 2016"

Bacterial cellulose-lactoferrin as an antimicrobial edible packaging

Bacterial cellulose (BC) films from two distinct sources (obtained by static culture with Gluconacetobacter xylinus ATCC 53582 (BC1) and from a commercial source (BC2)) were modified by bovine lactoferrin (bLF) adsorption. The functionalized films (BC+bLF) were assessed as edible antimicrobial packaging, for use in direct contact with highly perishable foods, specifically fresh sausage as a model of meat products. BC+bLF films and sausage casings were characterized regarding their water vapour permeability (WVP), mechanical properties, and bactericidal efficiency against two food pathogens, Escherichia coli and Staphylococcus aureus. Considering their edibility, an in vitro gastrointestinal tract model was used to study the changes occurring in the BC films during passage through the gastrointestinal tract. Moreover, the cytotoxicity of the BC films against 3T3 mouse embryo fibroblasts was evaluated. BC1 and BC2 showed equivalent density, WVP and maximum tensile strength. The percentage of bactericidal efficiency of BC1 and BC2 with adsorbed bLF (BC1+bLF and BC2+bLF, respectively) in the standalone films and in inoculated fresh sausages, was similar against E. coli (mean reduction 69 % in the films per se versus 94 % in the sausages) and S. aureus (mean reduction 97 % in the films per se versus 36 % in the case sausages). Moreover, the BC1+bLF and BC2+bLF films significantly hindered the specific growth rate of both bacteria. Finally, no relevant cytotoxicity against 3T3 fibroblasts was found for the films before and after the simulated digestion. BC films with adsorbed bLF may constitute an approach in the development of bio-based edible antimicrobial packaging systems.