Microorganisms and Their Importance in the Food Industry: Safety, Quality and Health Properties.

Microorganisms can play an important role in food production, especially through fermentation processes [...].

Comparative study of the bacterial community of organic and conventional cow's milk.

Agricultural practises such as conventional and organic farming can potentially affect the microbial communities in milk. In the present study, the bacterial diversity of milk was investigated using high-throughput sequencing on ten organic and ten conventional farms in the Azores, a region where milk production is largely based on year-round grazing systems. The microbiota of milk from both production systems was dominated by Bacillota, Pseudomonadota, Actinomycetota and Bacteroidota. The organic milk showed greater heterogeneity between farms, as reflected in the dispersion of diversity indices and the large variation in the relative abundances of the dominant genera. In contrast, conventionally produced milk showed a high degree of similarity within each season. In the conventional production system, the season also had a strong influence on the bacterial community, but this effect was not observed in the organic milk. The LEfSe analysis identified the genus Iamia as significantly (p < 0.05) more abundant in organic milk, but depending on the season, several other genera were identified that distinguished organic milk from conventionally produced milk. Of these, Bacillus, Iamia and Nocardioides were associated with the soil microbiota in organic farming.

Probiotic, technological, and health-related characteristics of lactobacilli isolated from breast milk.

AIMS: Isolation and characterization of lactobacilli from human milk and determination of their probiotic, technological, and in vitro health-promoting properties with a view to their potential use in food fermentation. METHODS AND RESULTS: Seven lactobacilli isolates were obtained from human milk and identified as Lacticaseibacillus paracasei (isolates BM1-BM6) and Lactobacillus gasseri (BM7). The isolates were examined in vitro for their technological, probiotic, and health-promoting potential. Overall, all isolates showed important technological properties based on the ability to grow in milk whey, a high to moderate acidification capacity and the absence of undesirable enzymatic activities. Lacticaseibacillus gasseri (BM7) differed from the L. paracasei isolates by the absence of several glycosidases and the inability to ferment lactose. Isolates L. paracasei BM3 and BM5 produced exopolysaccharides (EPS) from lactose. All isolates showed probiotic potential as they were tolerant to simulated gastrointestinal conditions, had high cell surface hydrophobicity, had not acquired resistance to relevant antibiotics and had no virulence characteristics. All L. paracasei showed high antimicrobial activity against various pathogenic bacteria and fungi, while L. gasseri showed a narrower spectrum of antimicrobial activity. All isolates showed health-promoting potential in vitro, as evidenced by high cholesterol-lowering activity, high ACE inhibitory activity and marked antioxidant activity. CONCLUSIONS: All strains showed excellent probiotic and technological properties for use in lactic ferments.

Prevention of Fungal Contamination in Semi-Hard Cheeses by Whey-Gelatin Film Incorporated with Levilactobacillus brevis SJC120.

Cheese whey fermented by lactic acid bacteria (LAB) was used to develop an edible film with antifungal properties. Five LAB strains isolated from artisanal cheeses were screened for antifungal activity and incorporated into a whey-gelatin film. Of the strains tested, Levilactobacillus brevis SJC120 showed the strongest activity against five filamentous fungi isolated from cheese and cheese-making environment, at both 10 °C and 20 °C. The cell-free supernatant from L. brevis inhibited fungal growth by more than 80%. Incorporation of bacterial cells into the film did not alter the moisture content, water vapor permeability, or mechanical and optical properties. The whey-gelatin film was also able to maintain the viability of L. brevis cells at 107 log CFU/g after 30 days at 10 °C. In cheeses wrapped with L. brevis film, the size of fungal colonies decreased by 55% to 76%. Furthermore, no significant differences (p > 0.05) were observed in cheese proteolysis or in the moisture, fat, and protein content of the cheese wrapped with films. The results showed that whey-gelatin film with L. brevis SJC120 can reduce the contamination of cheese with filamentous fungi and could be used as an alternative to conventional cheese preservation and packaging.

Distinct Bacterial Communities in São Jorge Cheese with Protected Designation of Origin (PDO).

São Jorge cheese is an iconic product of the Azores, produced from raw cow's milk and natural whey starter (NWS). Although it is produced according to Protected Designation of Origin (PDO) specifications, the granting of the PDO label depends crucially on sensory evaluation by trained tasters. The aim of this work was to characterize the bacterial diversity of this cheese using next-generation sequencing (NGS) and to identify the specific microbiota that contributes most to its uniqueness as a PDO by distinguishing the bacterial communities of PDO and non-PDO cheeses. The NWS and curd microbiota was dominated by Streptococcus and Lactococcus, whereas Lactobacillus and Leuconostoc were also present in the core microbiota of the cheese along with these genera. Significant differences (p < 0.05) in bacterial community composition were found between PDO cheese and non-certified cheese; Leuconostoc was found to play the chief role in this regard. Certified cheeses were richer in Leuconostoc, Lactobacillus and Enterococcus, but had fewer Streptococcus (p < 0.05). A negative correlation was found between contaminating bacteria, e.g., Staphylococcus and Acinetobacter, and the development of PDO-associated bacteria such as Leuconostoc, Lactobacillus and Enterococcus. A reduction in contaminating bacteria was found to be crucial for the development of a bacterial community rich in Leuconostoc and Lactobacillus, thus justifying the PDO seal of quality. This study has helped to clearly distinguish between cheeses with and without PDO based on the composition of the bacterial community. The characterization of the NWS and the cheese microbiota can contribute to a better understanding of the microbial dynamics of this traditional PDO cheese and can help producers interested in maintaining the identity and quality of São Jorge PDO cheese.

Evaluation of gamma-aminobutyric acid content in Portuguese cheeses with protected designation of origin status.

Health-conscious consumers are increasingly paying attention to healthy diets and focusing on natural bioactive compounds in foods and their effects on mental health. This opens new opportunities for the study of artisanal cheeses as biofunctional foods. In the work described in this Research Communication, the gamma-aminobutyric acid (GABA) content of seven different Portuguese cheeses produced from unpasteurized cow, sheep, and goat milk and granted with protected designation of origin (PDO) status was analysed. The PDO cheeses made from cow milk analysed in this study were São Jorge (3, 4, 7, 12 and 24 months of maturation) and Pico cheeses. PDO cheeses made from sheep milk were Serra da Estrela, Serpa, Nisa and Azeitão. Cheeses made from sheep and goat milk included Beira Baixa yellow cheese. The GABA content in the Azorean PDO cheeses (made from cow milk) ranged from 1.23 to 2.64 g/kg of cheese. Higher variations in GABA content were observed in cheeses made from sheep and goat milk (0.73-2.31 g/kg). This study provides information on the GABA content in different Portuguese PDO cheeses and shows that hard or semi-hard ripened cheeses are a suitable matrix for GABA production by lactic acid bacteria.

Application of enterocin-whey films to reduce Listeria monocytogenes contamination on ripened cheese.

An enterocin whey solution, obtained by growing Enterococcus faecalis L2B21K3 and L3A21K6 in sweet whey - enterocin whey solution (EWS), was incorporated into gelatin/glycerol films that were tested for the control of Listeria monocytogenes. The films containing enterocins produced by either strain (EWS L2 and EWS K6 films) were shown to serve as a suitable matrix for bacteriocin release, preserve the anti-listerial activity for up to 90 days. When applied in cheese, EWS L2 and EWS K6 films were able to reduce L. monocytogenes contamination to undetected levels after 20 or 30 days, respectively, and prevented the migration of this pathogen from the films to cheese. The incorporation of EWS into films did not affect (p < 0.05) moisture content, solubility, permeability (water vapor and limonene), and elongation at break compared to control films (without EWS). However, thickness, swelling index and tensile strength were higher (p < 0.05) in EWS films. These results suggest that active EWS gelatin/glycerol films could be an effective, and safe application to control L. monocytogenes in cheese. In addition, the use of cheese whey as a culture medium for the production of the bacteriocins complemented with the incorporation in films formulation as a packaging material represents an alternative approach to reuse this by-product of cheese production.

Consumption of fermented dairy products is associated with lower anxiety levels in Azorean university students.

A growing number of studies have found that the gut microbiota is involved in a variety of psychological processes and neuropsychiatric disorders, which include mood and anxiety disorders. Consumption of dairy products may contain bioactive compounds and probiotic bacteria with various therapeutic benefits. The aim of the study was to investigate possible associations between the frequency of consumption of different types of dairy products and the state of anxiety in university students. The subjects were 311 Azorean university students, 231 women and 80 men, with an average age of 20.5 years. Subjects completed a quantitative questionnaire on the frequency of dairy product consumption and a short version of the Spielberger State-Trait Anxiety Inventory (STAI) test. Among dairy products, semi-skimmed milk was the most commonly consumed, followed by cheese (ripened), drinking yogurt, skim milk, and set yogurt, while fresh cheese, whole milk, and dairy ice cream were the least common. Discriminant analysis showed that consumption of fermented products (yogurt and cheese) was significantly higher (P < 0.05) in the group with low anxiety level (score <40 in STAI test) than in the group with higher anxiety level (score ≥ 40). In this analysis, 62.4% of the initially grouped cases were correctly classified according to the frequency of fermented products consumption. No correlations were found between anxiety and unfermented dairy products. The results indicate that the consumption of fermented dairy products has a positive effect on reducing anxiety in young Azorean university students.

Lactic Acid Bacteria in Raw-Milk Cheeses: From Starter Cultures to Probiotic Functions.

Traditional cheeses produced from raw milk exhibit a complex microbiota, characterized by a sequence of different microorganisms from milk coagulation and throughout maturation. Lactic acid bacteria (LAB) play an essential role in traditional cheese making, either as starter cultures that cause the rapid acidification of milk or as secondary microbiota that play an important role during cheese ripening. The enzymes produced by such dynamic LAB communities in raw milk are crucial, since they support proteolysis and lipolysis as chief drivers of flavor and texture of cheese. Recently, several LAB species have been characterized and used as probiotics that successfully promote human health. This review highlights the latest trends encompassing LAB acting in traditional raw milk cheeses (from cow, sheep, and goat milk), and their potential as probiotics and producers of bioactive compounds with health-promoting effects.

Application of Enterococcus malodoratus SJC25 for the Manufacture of Whey-Based Beverage Naturally Enriched with GABA.

Gamma-aminobutyric acid (GABA) is used as a dietary supplement because of its health-promoting properties. However, concern over the use of synthetic products has increased the demand for foods that are naturally fortified with GABA. In addition, excess whey is a major concern for the dairy industry due to the high cost of treating it. Here, we report the use of a novel Enterococcus malodoratus strain isolated from cheese to produce sweet whey beverages naturally enriched with GABA. After the screening of cheese isolates, E. malodoratus strains were identified as high GABA producers. One beverage was prepared from pasteurized sweet whey enriched in glutamic acid and E. malodoratus SJC25. The fermented beverages were supplemented with a fruit preparation and subjected to chemical, microbiological and sensory analysis. The bacterial counts and GABA content were maintained until storage at 4 °C for 14 days. High conversion rates of glutamic acid to GABA (50-71%) were obtained in the beverages. The GABA content in whey-based beverages reached 250-300 mg/100 mL, which is equivalent to the content of commercially available GABA supplements. The beverages received a positive rating (4/5) by the taste panel. To our knowledge, this is the first report on E. malodoratus as a potential GABA producer.

Exopolysaccharides Produced by Lactic Acid Bacteria: From Biosynthesis to Health-Promoting Properties.

The production of exopolysaccharides (EPS) by lactic acid bacteria (LAB) has attracted particular interest in the food industry. EPS can be considered as natural biothickeners as they are produced in situ by LAB and improve the rheological properties of fermented foods. Moreover, much research has been conducted on the beneficial effects of EPS produced by LAB on modulating the gut microbiome and promoting health. The EPS, which varies widely in composition and structure, may have diverse health effects, such as glycemic control, calcium and magnesium absorption, cholesterol-lowering, anticarcinogenic, immunomodulatory, and antioxidant effects. In this article, the latest advances on structure, biosynthesis, and physicochemical properties of LAB-derived EPS are described in detail. This is followed by a summary of up-to-date methods used to detect, characterize and elucidate the structure of EPS produced by LAB. In addition, current strategies on the use of LAB-produced EPS in food products have been discussed, focusing on beneficial applications in dairy products, gluten-free bakery products, and low-fat meat products, as they positively influence the consistency, stability, and quality of the final product. Highlighting is also placed on reports of health-promoting effects, with particular emphasis on prebiotic, immunomodulatory, antioxidant, cholesterol-lowering, anti-biofilm, antimicrobial, anticancer, and drug-delivery activities.

Application of Bacteriocins and Protective Cultures in Dairy Food Preservation.

In the last years, consumers are becoming increasingly aware of the human health risk posed by the use of chemical preservatives in foods. In contrast, the increasing demand by the dairy industry to extend shelf-life and prevent spoilage of dairy products has appeal for new preservatives and new methods of conservation. Bacteriocins are antimicrobial peptides, which can be considered as safe since they can be easily degraded by proteolytic enzymes of the mammalian gastrointestinal tract. Also, most bacteriocin producers belong to lactic acid bacteria (LAB), a group that occurs naturally in foods and have a long history of safe use in dairy industry. Since they pose no health risk concerns, bacteriocins, either purified or excreted by bacteriocin producing strains, are a great alternative to the use of chemical preservatives in dairy products. Bacteriocins can be applied to dairy foods on a purified/crude form or as a bacteriocin-producing LAB as a part of fermentation process or as adjuvant culture. A number of applications of bacteriocins and bacteriocin-producing LAB have been reported to successful control pathogens in milk, yogurt, and cheeses. One of the more recent trends consists in the incorporation of bacteriocins, directly as purified or semi-purified form or in incorporation of bacteriocin-producing LAB into bioactive films and coatings, applied directly onto the food surfaces and packaging. This review is focused on recent developments and applications of bacteriocins and bacteriocin-producing LAB for reducing the microbiological spoilage and improve safety of dairy products.

Characterization and Application of Antilisterial Enterocins on Model Fresh Cheese.

Enterococcus faecalis strains isolated from an artisanal cheese were selected based on enterocin production against Listeria monocytogenes. The strains formed biofilms and presented high hydrophobic character and good autoaggregation and coaggregation capacity with L. monocytogenes. Strains L3A21M3 and L3B1K3 presented high survival under gastrointestinal conditions, were able to adhere to human intestinal cells (Caco-2 and HT-29), and blocked the adhesion and invasion of L. monocytogenes. The antilisterial activity of enterocins was not affected by pH (2 to 12), heating (100°C), and chemical and surfactant agents. However, strains L3A21M3 and L3A21M8 produced thermolabile enterocins, which were also sensible to extreme pH values. Enterocins exhibited a bacteriostatic mode of action against L. monocytogenes, and maximum production was observed during the stationary phase. Common enterocin structural genes were not detected by PCR amplification with specific primers, although an exhaustive screening was not performed. The enterocin produced by the L3B1K3 strain was purified and applied to model cheeses contaminated with L. monocytogenes. This enterocin reduced survival of L. monocytogenes on fresh cheeses in a dose-dependent manner. The highest dose tested (2,048 arbitrary units per g of cheese) was effective in reducing the pathogen counts to undetectable values throughout storage (6 to 72 h). These results suggest that these strains have great potential to be used as biopreservatives in the food industry and also as probiotics, with the potential to prevent L. monocytogenes gastrointestinal infection.

Implante transcateter de bioprótese valvular pulmonar: revisão sistemática da literatura / Transcatheter pulmonary valve implantation: systematic literature review

A correção cirúrgica de algumas cardiopatias congênitas complexas envolve a reconstrução da via de saída do ventrículo direito com a interposição de homoenxertos, biopróteses, enxertos de jugular bovina ou outros condutos valvulados entre o ventrículo direito e o tronco da artéria pulmonar. Apesar de essas cirurgias poderem ser realizadas com baixa mortalidade, a vida útil das válvulas ou dos condutos implantados é normalmente pequena (< 10 anos), seja por degeneração e/ou calcificação. Graus variáveis de estenose pulmonar na maioria das vezes associada a insuficiência pulmonar são consequências da degeneração dos condutos. Em 2000, Bonhoeffer et al. foram os primeiros a relatar o implante transcateter de bioprótese valvular pulmonar (ITVP) com um dispositivo que posteriormente foi denominado de válvula Melody® (Medtronic, Minneapolis, Estados Unidos). A técnica foi inicialmente desenvolvida para limitar a necessidade de múltiplos procedimentos cirúrgicos, substituindo, em última análise, uma nova troca cirúrgica valvular. Estudos subsequentes na Europa e Estados Unidos atestaram para a segurança e eficácia dessa técnica em um número maior de pacientes. Como a Agência Nacional de Vigilância Sanitária (Anvisa) concedeu a aprovação para o uso clínico da válvula biológica pulmonar transcateter Melody® em fevereiro de 2013, consideramos necessária e oportuna a avaliação judiciosa da utilização dessa nova tecnologia antes que ela fosse aplicada em larga escala em nosso país. O objetivo deste estudo foi realizar uma revisão sistemática da literatura sobre o ITVP em pacientes com disfunções de homoenxertos, condutos valvulados e biopróteses implantados cirurgicamente na via de saída do ventrículo direito.

Surgical repair of some complex congenital heart diseases involves reconstruction of the right ventricular outflow tract using homografts, bioprostheses, bovine jugular grafts or other valved conduits between the right ventricle and the main pulmonary artery. Although these surgical procedures may be performed with low mortality rates, the life span of these implanted valves or conduits is usually short (< 10 years) due to either degeneration and/or calcification. Variable degrees of pulmonary stenosis, often associated with pulmonary insufficiency, are consequences of conduit degeneration. In 2000, Bonhoeffer et al. were the first to report the transcatheter pulmonary valve implantation (TPVI) of a bioprosthetic pulmonary valve later named Melody® valve (Medtronic, Minneapolis, USA). The technique was initially developed to limit the need for multiple surgical procedures, and, ultimately, to work as a surrogate of a new surgical valve replacement. Subsequent clinical studies in Europe and the United States confirmed the safety and efficacy of this technique in a larger number of patients. Since the National Sanitary Surveillance Agency (Agência Nacional de Vigilância Sanitária - Anvisa) granted approval for clinical use of the Melody® transcatheter pulmonary biological valve in February 2103, we deemed that a judicious assessment of this new technology was timely and necessary before the widespread use in our country. The objective of this study was to perform a systematic literature review on the use of TPVI in patients with dysfunctional homografts, valved conduits and bioprostheses implanted surgically in the right ventricular outflow tract.

[Serial clinical and echocardiographic evaluation in children with Marfan syndrome]. / Avaliação clínico-cardiológica e ecocardiográfica, seqüencial, em crianças portadoras da síndrome de Marfan.

OBJECTIVE: To describe the clinical cardiac manifestations and temporal evolution of Marfan syndrome in children; to estimate the incidence of annuloaortic ectasia and mitral valve prolapse; and to evaluate tolerability and efficacy of beta-blockers in these patients. METHODS: During one year, 21 children with Marfan syndrome underwent serial clinical and echocardiographic examinations. Echocardiograms assessed: the presence of mitral valve prolapse, aortic root diameter, mitral and aortic valves regurgitation, and aortic enlargement during beta-blocker therapy. Eleven patients had two measurements of the aortic root taken one year apart. RESULTS: The children were asymptomatic throughout the study. Mitral prolapse was found in 11 (52%) children. Annuloaortic ectasia occurred in 16 (76%) patients and found to be mild in 42.8%, moderate in 9.5%, and severe in 23.8%. One of these patients underwent aortic valve replacement and repair of the ascending aorta by the Bentall-De Bono technique, with good results. Heart rate decreased by 13.6% (from 85 to 73 bpm; p < 0.009) with the use of beta-blockers; however, aortic root diameter increased by 1.4 mm/year (p < 0.02). One child could not be given beta-blockers due to bronchial asthma, and no significant side effects were observed in the remaining children, including one who also had bronchial asthma. CONCLUSION: The children remained asymptomatic throughout the study, the use of beta-blockers led to a significant decrease in heart rate, and no significant adverse effects were observed. Contrary to the literature, incidence of annuloaortic ectasia was high among the study population, greater than that of mitral valve prolapse, even during beta-blocker therapy.

Avaliacão clínico-cardiológica e ecocardiográfica, seqüencial, em criancas portadoras da síndrome de Marfan / Serial clinical and echocardiographic evaluation in children with Marfan syndrome

OBJETIVO: Descrever a apresentacão clínica cardiológica e a evolucão temporal, estimar a incidência de ectasia ânulo-aórtica e de prolapso da valva mitral, e avaliar a tolerância e a efetividade dos betabloqueadores em criancas com síndrome de Marfan. MÉTODOS: Foram submetidas a exame clínico e ecocardiográfico seriado, durante um ano, 21 criancas com síndrome de Marfan. No ecocardiograma foram analisados: presenca de prolapso mitral, diâmetro da raiz aórtica, refluxos das valvas mitral e aórtica, e o crescimento dos diâmetros aórticos na vigência de betabloqueadores. Em 11 pacientes foi possível obter duas medidas da raiz aórtica no intervalo de um ano. RESULTADOS: Durante o estudo as criancas não apresentaram sintomas. Prolapso mitral foi encontrado em 11 (52 por cento) criancas. Ectasia ânulo-aórtica ocorreu em 16 (76 por cento) pacientes, sendo de grau discreto em 42,8 por cento, moderado em 9,5 por cento, e importante em 23,8 por cento. Um desses pacientes foi submetido com sucesso à cirurgia de Bentall DeBono. Com o uso de betabloqueador a freqüência cardíaca diminuiu 13,6 por cento (de 85 para 73 bpm; p < 0,009), mas houve um crescimento da raiz aórtica de 1,4 mm/ano (p < 0,02). Uma crianca não pôde receber betabloqueador em razão de asma brônquica, e não foram observados efeitos colaterais significativos nas outras criancas, incluindo uma com asma brônquica. CONCLUSAO: Os resultados obtidos sugerem que, no período observado, as criancas permaneceram assintomáticas, o uso de betabloqueadores diminuiu significativamente a freqüência cardíaca e não se acompanhou de efeitos adversos significativos. Ao contrário da literatura, a incidência de ectasia ânulo-aórtica foi elevada e maior do que a de prolapso valvar mitral, tendo crescimento mesmo na vigência de uso eficaz de betabloqueador.

Estenose aórtica supravalvar complicada por endarterite aórtica e formaçäo de aneurisma micótico / Supravalvar Aortic Stenosis Complicated by Aortic Endarteritis and Mycotic Aneurysm Formation

Paciente do sexo masculino, 11 anos, portador de estenose aórtica supravalvar, tendo como complicaçäo aneurismas micóticos em aorta ascendente secundários a endocardite bacteriana. Os aneurismas foram diagnosticados através de ecocardiograma-controle ao término de tratamento clínico da endocardite, aparentemente sem intercorrências. A angiografia confirmou o diagnóstico, tendo sido os aneurismas ressecados cirurgicamente. Após 6 meses de cirurgia, o paciente continua bem