Qualidade higiênico-sanitária de suco de laranja in natura e estabelecimentos comerciais / Hygiene and sanitary quality of in natura orange juice and commercial establishments

O objetivo deste estudo foi analisar a qualidade microbiológica de suco de laranja in natura em Presidente Prudente (SP) e estabelecimentos comerciais. Foi avaliada a qualidade higiêncio-sanitária do ambiente de trabalho mediante um check-list e a qualidade do suco de laranja por contagem em placa. Os resultados foram submetidos à análise de variância (ANOVA) para dados não paramétricos (Kruskal-Wallis) com p <0,05. A maioria dos estabelecimentos apresentou boas práticas de higiene adequadas. Não foi confirmada a presença de coliformes termotolerantes. Para os demais parâmetros microbiológicos foram observadas altas contaminações em algumas amostras de suco. As bactérias ácido-láticas (BAL's) apresentaram contagem entre 3,15 (dp=0,21) a 5,68 (dp=0,01) log UFC/mL, e sua avaliação inibitória foram satisfatórias, uma vez que conseguiram inibir Escherichia coli (15 a 27 mm) e Listeria monocytogenes (23 a 27 mm). A adoção de medidas de boas práticas de higiene, além da educação continuada dos manipuladores de alimentos, promove a redução da contaminação.

Current paper analyzes the microbiological quality of in natura orange juice in Presidente Prudente, Brazil, and in commercial establishments. Hygiene and sanitary conditions of work environment was investigated through a check-list and the quality of orange juice was analyzed by plate counts for ANOVA results for non-parameter data (Kruskal-Wallis) at p<0.05. Most commercial establishments had good hygiene practice and thermo-tolerant coliforms were not extant. There were, however, high contaminations in several juice samples. Acid-lactic bacteria had counts between 3.15(dp=0.21) and 5.68(dp=0.01) log CFU/mL. Inhibitory evaluation was satisfactory since their impaired Escherichia coli (15 - 27 mm) and Listeria monocytogenes (23 - 27mm). Good practice in hygiene and continued education by food handlers cause a reduction of contamination.

Bio-preservative Activities of Partially Purified Bacteriocin Extracts of Lactobacillus mindensis TMW and Lactobacillus tucceti CECT 5920 Isolated from Nigerian Fermented Foods

The preservative potentials of lactic acid bacteria (LAB) recovered from some Nigerian traditional fermented foods were assessed by inoculating 0.1 ml aliquots of suitable dilutions of the food samples on De Man Rogosa Sharpe (MRS) agar fortified with 50mg of nystatin. The isolates were assessed for their ability to produce bacteriocin using Agar Well Diffusion assay method. By using (GTG)5-PCR and 16s rDNA sequencing tools, two bacteriocin-producing LAB namely Lactobacillus tucceti CECT 5920 and Lactobacillus mindensis TMW were identified. Both LAB isolates had equal level of bacteriocin activity. Studies on inhibitory activity of partially purified bacteriocin extracts showed that temperature of 35°C had maximum effect on bacteriocin antimicrobial activity of L. tucceti CECT 5920 against Staphylococcus aureus NCTC 8325 and Escherichia coli 0157:H7, while pH had same effects on both LAB isolates against the test bacteria. Maximum tolerance of acidic medium was exhibited by both LAB isolates at pH 3-8. Bacteriocin inhibitory activity was best against both test bacteria at 0.2% concentration of NaCl. Combination of ginger with partially purified bacteriocin sample from both LAB isolates had reduction effect on both test pathogens for both Lactic acid bacteria isolates. When stored for 14 days, bacteriocin activity was optimum for the first day against both test pathogens, but decreased progressively with increased in storage time. The two LAB isolates had similar inhibitory activity against both test pathogens. L. tucceti CECT 5920 gave greater reduction result (90.03%) on S. aureus NCTC 8325 in fish sample and 78.07% against E. coli 0157:H7 in meat sample while L mindensis TMW had highest significant reduction effect (90.12%) in fish sample against S. aureus NCTC 8325 and 77.80% against E. coli 0157:H7 in fish sample. Both LAB isolates will perform well as preservative agents in food preservation as they showed production of bacteriocin which has antimicrobial activity and rapid acidification in growth medium.

Bacteriocin-like inhibitory substance in aquaculture: a classic method of protein precipitation for a new aplicability / Substância inibidora tipo bacteriocina na aquicultura: método clássico de precipitação de proteínas para novas aplicações

Techniques to decrease losses from bacterial diseases are always important to improve the fish production. The use of antagonistic substances (bacteriocins) has been proven to be a viable option. The aim of this study was to evaluate different methods of purification for bacteriocin like inhibitory substances (BLIS). For the purification process, we isolated and used two Gram-positive bacilli that produce antagonistic substances for pathogens in aquaculture. Tests for detection of interfering factors were also performed. After the confirmation that the antagonistic action was due the BLIS activity, we carried out the purification methods. The methods tested were: cell free supernatant, acid extraction and ammonium sulfate precipitation at two concentrations (20 and 50%). Salmonella Tiphy CFP/IAL1472 and Aeromonas hydrophila (isolated in a tilapia production environment) were used as indicators of the efficiency of extracts in controlling pathogenic potentials. Ammonium sulfate precipitation at 50% was the most appropriate for purifying the antagonistic substance for both indicators. The extracts of the two isolates remained active for 22 days at 25ºC. These are promising results regarding the water and fish health without the use of antibiotics, in this manner being a safer environmental practice.

Técnicas para diminuir as perdas causadas por doenças bacterianas são importantes para melhorar continuamente a produção de pescado. O uso de substâncias antagônicas (bacteriocinas) tem-se mostrado uma opção viável. O objetivo do trabalho foi avaliar diferentes métodos de purificação de bacteriocinas como substâncias inibidoras (BLIS). Dois bacilos Gram-positivos, produtores de substâncias antagonistas para agentes patogênicos da aquicultura, foram utilizados em processos de purificação. Depois de confirmada a ação antagônica pela atividade de BLIS, os métodos de purificação foram realizados. Os métodos testados foram: células livres de sobrenadante, extração ácida e precipitação por sulfato de amônia em duas concentrações (20 e 50%). Salmonella Typhi PCP/IAL1472 e Aeromonas hydrophila (isolada de um ambiente de tilapicultura) foram utilizadas como indicadores de eficiência dos extratos. O precipitado por sulfato de amônio a 50% foi o mais adequado para purificar a substância antagonista para ambos os isolados indicadores. Os extratos dos dois isolados permaneceram ativos por 22 dias em 25ºC. Estes resultados são promissores do ponto de vista da manutenção da sanidade da água e dos peixes, sem uso de antibióticos, constituindo uma prática ambientalmente mais segura.

Technology and safety assessment for lactic acid bacteria isolated from traditional Bulgarian fermented meat product "lukanka"

Abstract The present work discusses the technological and new selection criteria that should be included for selecting lactic acid bacteria for production of fermented meat. Lactic acid bacteria isolated from Bulgarian traditional fermented "lulanka" salami was studied regarding some positive technological parameters (growth at different temperature, pH, and proteolytic activity). The presence of genes related to the virulence factors, production of biogenic amines, and vancomycin resistance were presented in low frequency in the studied lactic acid bacteria. On the other hand, production of antimicrobial peptides and high spread of bacteriocin genes were broadly presented. Very strong activity against L. monocytogenes was detected in some of the studied lactic acid bacteria. In addition, the studied strains did not present any antimicrobial activity against tested closely related bacteria such as Lactobacillus spp., Lactococcus spp., Enterococcus spp. or Pediococcus spp. To our knowledge this is the first study on the safety and antimicrobial properties of lactic acid bacteria isolated from Bulgarian lukanka obtained by spontaneous fermentation.

determinación de bacteriocinas en muestras de consorcios microbianos nativos de ecosistemas de manglar en el departamento del atlántico, como fuente potencial de nuevos tratamientos biomédicos / The mangroves are ecosystems of high primary productivity; they are rich in organic matter and have high microbial diversity. The pressure of the physical conditions of the mangrove ecosystems has been linked to the production of special metabolites and unique molecular structures for microorganisms. Because of the developing of microbial resistance to antimicrobials in the world, it is necessary

Los manglares son ecosistemas con gran diversidad microbiana; la presión de las condiciones físicas de este, se ha relacionado con la producción de metabolitos con estructuras moleculares únicas para los microorganismos. Dado el desarrollo de resistencia bacteriana a antimicrobianos a nivel mundial, se hace necesaria la búsqueda de nuevas soluciones que nos permitan contrarrestar los efectos de dichos patógenos. En este estudio, se buscó aislar, identificar y evaluar la actividad antimicrobiana de bacteriocinas producidas por microorganismos nativos del ecosistema de Manglar de la Ciénaga de Mallorquín, frente a microorganismos patógenos de interés clínico. Se comprobó actividad antimicrobiana leve del extracto CN11, CN 8, P4C3, frente a S. Aureus ATCC 25923, actividad antimicrobiana leve del extracto de P4C3 frente a E. coli BLEE, actividad antimicrobiana leve frente a Klebsiella Pneumoniae ATCC 700603 de los extractos P4C3 y CN9; y actividad antimicrobiana moderada para el caso del extracto proteico de la cepa CN9 frente a E.coli ATCC 25922

The mangroves are ecosystems of high primary productivity; they are rich in organic matter and have high microbial diversity. The pressure of the physical conditions of the mangrove ecosystems has been linked to the production of special metabolites and unique molecular structures for microorganisms. Because of the developing of microbial resistance to antimicrobials in the world, it is necessary the research of new solutions that allow to counteract the effect of those pathogens. On this study, I was looking isolate, identify and evaluate the antimicrobial bacteriocins activity produced by native microbial consortia of mangrove swamp at the Mallorquín swamp, against pathogens microorganisms of clinical interest. Mild antimicrobial activity of the extract CN11, CN 8, P4C3, was found against S. aureus ATCC 25923, mild antimicrobial activity of P4C3 extract was found against E. coli BLEE, mild antimicrobial activity of the extracts P4C3 y CN9 against Klebsiella Pneumoniae ATCC 700603; moderate antimicrobial activity for protein extract of CN9 against E. coli ATCC 25922.

Secondary metabolites from Streptococcus mutans and their ecological roles in dental biofilm / 生物工程学报

Dental biofilms are composed of hundreds of bacterial species, among which Streptococcus mutans is widely recognized as the major pathogen of dental caries. The cariogenic potential of S. mutans is related to its ability to form a robust biofilm on the tooth surface and its acidogenic and acid-tolerant properties. Co-evolution of S. mutans with the host has resulted in the diversity of secondary metabolism of S. mutans in strain level. A variety of secondary metabolites, including 10 bacteriocins (mutacins) and one hybrid Polyketide/Non-Ribosomal Peptide type compound, have been characterized. Studies on these secondary metabolites indicate that they play a significant role either in interspecies or in inter-kingdom interactions in the dental biofilm. As more S. mutans strains are isolated and sequenced, additional secondary metabolites with novel functions will be discovered. The study of secondary metabolites in S. mutans is anticipated to be helpful for oral disease treatment and prevention by providing new strategies.

Screening of the novel colicinogenic gram-negative rods against pathogenic Escherichia coli O157:H7.

Purpose: Escherichia coli (E. coli) O157:H7 is gram‑negative enteric pathogen producing different types of Shiga toxin. This bacterium is the most corporate cause of haemorrhagic colitis in human. Administration of antibiotics (particularly sulfa drugs) against this pathogen is a debatable topic as this may increase the risk of uremic syndrome; especially in children and aged people. Around the world, microbiologists are in search of alternative therapeutic methods specially probiotics against this pathogen. In the present study, we have focused on the investigation of alternate bio‑therapeutics (probiotics) for the treatment of patients infected with E. coli O157:H7. This study is based on the identification of colicin‑producing gram‑negative bacteria (particularly enterobacteriaceae) which can competently exclude E. coli O157:H7 from the gut of the infected individual. Materials and Methods: Hundred samples from human, animal faeces and septic tank water were analysed for nonpathogenic gram‑negative rods (GNRs). Results: Out of these samples, 175 isolates of GNRs were checked for their activity against E. coli O157:H7. Only 47 isolates inhibited the growth of E. coli O157:H7, among which majority were identified as E. coli. These E. coli strains were found to be the efficient producers of colicin. Some of the closely related species i. e., Citrobacter sp, Pantoea sp. and Kluyvera sp. also showed considerable colicinogenic activity. Moreover, colicinogenic species were found to be nonhaemolytic, tolerant to acidic environment (pH 3) and sensitive to commonly used antibiotics. Conclusion: Nonhaemolytic, acid tolerant and sensitive to antibiotics suggests the possible use of these circulating endothelial cells (CEC) as inexpensive and inoffensive therapeutic agent (probiotics) in E. coli O157:H7 infections.

Antimicrobial Activity against Some Saprophytic and Pathogenic Microorganisms of Bacillus species Strains Isolated from Natural Spring Waters in Bulgaria.

It is well known that many members of genus Bacillus possess an antimicrobial activity against a variety of microorganisms. In this study we present a primary screening for antimicrobial activity against some saprophytic and pathogenic microorganisms of nineteen strains identified as Bacillus cereus, Bacillus thuringiensis and Bacillus subtilis, isolated from eight natural thermal springs in two districts - Haskovo and Stara Zagora, Bulgaria. The inhibitory activities of the Bacillus sp. strains were determined by agar-well diffusion method. Test microorganisms were preliminarily included into the agar medium, whereas the Bacillus sp. strains were added to the wells. After 48 hours of incubation, the antimicrobial effects were determined by measuring the diameter of zones of inhibition around the wells. Most of Bacillus sp. strains showed high antimicrobial activitiy against the molds Penicillium sp., Aspergillus oryzae, Aspergillus niger, Aspergillus awamori, Fusarium moliniforme and Rhizopus sp. Inhibitory activity against the mold Mucor sp. and bacterium Enterococcus faecalis ranged between low and moderate. Two of the strains (Bacillus cereus 52/GI1 and Bacillus thuringiensis 56/H3) possessed moderate antimicrobial activity against bacterium Pseudomonas aeruginosa and yeasts Saccharomyces cerevisiae. One strain (Bacillus subtilis 47/YA1) had high activity against the mold Mucormucedo; one strain (Bacillus cereus 36/GI6) showed moderate activity against yeasts Candida utilis, while bacterium Escherichia coli was not inhibited at all.

Adición de Carnobacterium maltaromaticum CB1 en chorizo y morcilla empacados al vacío, para inhibir el crecimiento de Listeria monocytogenes / Addition of Carnobacterium maltaromaticum CB1 in vacuum packaged chorizo and morcilla, to inhibit the growth of Listeria monocytogenes

Antecedentes: En años recientes la demanda de productos alimenticios percibidos como “naturales” se ha incrementado de manera importante, los cuales no contienen dentro de sus ingredientes conservantes o aditivos de origen químico o artificial. Al retirar de la fórmula estos conservantes/aditivos artificiales se puede generar en el producto un medio ideal de crecimiento de bacterias alterantes o patógenas. Esto es particularmente cierto en productos cárnicos procesados empacados al vacío, donde su alta actividad acuosa, bajo pH y un largo periodo de almacenamiento a condiciones de refrigeración generan un ambiente ideal para el crecimiento de microorganismos patógenos como Listeria monocytogenes. Por tanto, esto genera la necesidad de nuevas y efectivas tecnologías que permitan su control y eliminación. Los Bio-Conservantes (adición de bacterias vivas a los productos cárnicos) ofrecen una solución ideal a este tipo de problemas directamente relacionados con la seguridad alimentaria, y a la vez satisfacen la demanda por parte de los consumidores de productos saludables. Objetivos: Determinar si el cultivo C. maltaromaticum CB1 puede controlar el crecimiento de una cepa nativa de L. monocytogenes en morcilla y chorizo empacados al vacío (película de baja permeabilidad al oxigeno). Métodos: Tres lotes diferentes de chorizo y morcilla producidos a nivel industrial fueron posteriormente inoculados con una cepa nativa de L. monocytogenes a un nivel de 102 UFC/g junto con el bio-conservante C. maltaromaticum CB1 a un nivel de 103 UFC/g. A los tratamientos denominados como control no se les aplicó el bio-conservante. Después de ser empacados al vacío, los productos fueron almacenados a dos temperaturas diferentes de 4°C (refrigeración) y 8°C (abuso de temperatura) durante 35 días. En intervalos de 7 días se hizo recuentos del crecimiento de la L. monocytogenes utilizando agar Oxford...

Isolation of bacteriocin - producing lactic acid bacteria from 'Ugba' and 'Okpiye', two locally fermented nigerian food condiments

In this work, 100 samples each of 'ugba' and 'okpiye' were evaluated for the presence of bacteriocin producing lactic acid bacteria. Thirty strains showing antibacterial activity against at least one of the indicator organisms were selected from a total of 752 colonies isolated from the condiments. Out of the 30, only five strains retained activity after the pH of the broth supernatant was adjusted to 6.5. When evaluated by the agar-well diffusion assay, the spectra of inhibitory activity showed that Staphylococcus aureus was the most sensitive indicator organism tested, while Listeria monocytogenes was the most resistant. One strain (UG 2) was active against Escherichia coli. The assays using the cell-free supernatant of the cultures showed that the bacteriocins were completely inactivated by the proteolyses as well as by the chloroform treatment. In ethanol, the activity of the compounds was only partially modified. When incubated in a water bath at 80°C for 30 min, no significant activity loss was recorded. The antimicrobial activity of the bacteriocins produced by the lactic acid bacteria has potential for use in biopreservation of condiments against the spoilage and food - borne pathogens.

Fungicidal effect of bacteriocins harvested from Bacillus spp

Aims: This study investigated the ability of bacteriocins isolated from Bacillus spp. (Bacillus species) to inhibit four different yeast isolates obtained from common food products (nono, yoghurt, ogi and cheese) commonly consumed by Nigerians with minimal heat treatment. Methodology and results: Forty-five Bacillus spp. was isolated and identified from common food products using cultural, morphological, physiological and biochemical characteristics. These isolates were tested for antimicrobial activity against Salmonella enteritidis (3), Micrococcus luteus (1) and Staphylococcus aureus (2). Eight bacteriocin producing strains were identified from an over- night broth culture centrifugated at 3500 revolutions for five minutes. Fungicidal effects of these bacteriocins were tested against four yeast strains using the Agar Well Diffusion method. The bacteriocins produced wide zones of inhibition ranging from 5.9±0.000 to 24.00±0.000 mm against the 4 yeast strains tested. There was a significant difference (at p<0.05) between the yeast organisms and the bacteriocins from the Bacillus spp. Conclusion, significance and impact of study: The study reveals the antifungal property of bacteriocins from Bacillus spp. and serves therefore as a base for further studies in its use in the control of diseases and extension of shelf-life of products prone to fungi contamination.

Antimicrobial activity of lactic acid bacteria and the spectrum of their biopeptides against spoiling germs in foods

The objective of this study was to isolate LAB from dairy, meat products and agro-industrial wastes and to investigate their antagonist activity. A total of 141 isolates were screened for the inhibitory effect on ten indicator strains in the agar spot test. Results showed that strain LBbb0141 contained antimicrobial compound with wide spectrum that inhibited the growth of ten indicator Gram-positive and Gram-negative strains. The bacteriocin activity attained its maximum value using the MRS agar at initial pH 7.5 and 30°C incubation temperature.

Genes de virulencia y bacteriocinas en cepas de Enterococcus faecalis aisladas desde diferentes muestras clínicas en la Región del Maule, Chile / Virulence genes and bacteriocins in Enterococcus faecalis strains isolated from different clinical samples in Maule Region, Chile

The presence of virulence genes (VG) and bacteriocins from different clinical samples was studied in Enterococcus faecalis isolated from urinary tract infections (UTI), bacteremia and endodontitis and was correlated with haemolysin and gelatinase activity. We evaluated the presence of VG by PCR in 150 strains of E. faecalis including cylA, aggA, efaA, eep, gelE, esp, as-48, bac31, entL50A/B, entA, entP, entB, enlA andentl071. Haemolysin and gelatinase activity was studied. gelE and cylA genes expressed hemolysin and gelatinase, respectively. This activity was observed in some strains of bacteremia, UTI and endodontitis. The highest number of VG was detected in bacteremic strains, being aggA and entA genes the most frequent. efaA, esp, entA, entL50A/B were associated with their clinical origin (p < 0.05). The most common genetic profile was aggA-eep-enlA-entL50A/B. E. faecalis from UTI, bacteremia and endodontitis presented different gene combinations. Some of the genes studied were related to their clinical origin. The results obtained in this study are similar to those reported in other countries.

Desde diferentes muestras clínicas se determinó la presencia de genes codificantes de factores de virulencia (FV) y bacteriocinas en Enterococcus faecalis aislados desde infecciones del tracto urinario (ITU), bacteriemias y endodontitis, correlacionándose con la actividad hemolisina y gelatinasa. En 150 cepas de E. faecalis fue evaluada mediante RPC la presencia de cylA, aggA, efaA, eep, gelE, esp, as-48, bac31, entL50A/B, entA, entP, entB, enlA, y ent1071 determinándose actividad hemolisina y gelatinasa. Los genes cylA y gelE expresaron hemolisina y gelatinasa, respectivamente. Esta actividad fue observada en algunas de las cepas causantes de bacteriemia, ITU y endodontitis. El mayor número de genes estudiados se detectó en cepas bacteriémicas. Los genes aggA y entA, fueron los más frecuentes. Los genes efaA, esp, entL50/AB y entA se asociaron a su origen clínico (p < 0,05). El perfil genético más recurrente fue aggA-eep-enlA-entL50A/B. Enterococcusfaecalis de ITU, bacteriemias y endodontitis presentaron distintas combinaciones génicas. AAlgunos de los genes estudiados se relacionaron con su origen clínico. Los resultados obtenidos son similares a los reportados en otros países.

Purification and characterization of NISIN produced by lactococcus lactis isolated from Indian curd.

Lactococcus lactis isolated from traditional dairy Indian curd. Strains were preliminarily identified by PCR analysis and partial 16S rRNA confirmed that N5 were 100% identical to Lactococcus. lactis sp. lactis. The results revealed that only the bacteriocin produced from strain N5 was shown as being active against mostly gram positive bacteria The bacteriocin produced purified by precipitation followed by loading with gel chromatography. The partially purified bacteriocin was found to be stable over a wide range of pH, temperature and enzymes. The molecular weight of the peptide was judged to be 3.5 kDa by SDSpolyacrylamide gel electrophoresis.and conform to the result of mass spectrometry by maldi-tof test which calculated the mass of 3354.07 Da for nisin.These results indicate that bacteriocin produced by L. lactis sp. lactis N5 is a nisin.

Interações entre bactérias láticas produtoras de bacteriocinas e a microbiota autóctone de charque / Interactions between bacteriocin-producing lactic acid bacteria and the autochthonous microbiota from charqui

O charque é um produto cárneo tipicamente brasileiro, salgado e seco ao sol, ainda produzido de maneira artesanal. Durante sua produção há uma etapa de fermentação, realizada pela microbiota naturalmente presente na matéria-prima, o que dificulta a padronização do produto, e pode influenciar negativamente em suas características sensoriais e qualidade microbiológica. O controle da etapa de fermentação do charque seria uma alternativa para minimizar este problema e, neste contexto, as bactérias láticas produtoras de bacteriocinas se enquadram de forma interessante. A microbiota autóctone de charque inclui principalmente bactérias láticas e micro-organismos halofílicos e halotolerantes, sendo assim, este produto apresenta potencial como fonte para o isolamento de novas bactérias láticas produtoras de bacteriocinas. Assim, este trabalho teve por objetivo isolar e identificar culturas de bactérias láticas produtoras de bacteriocinas naturalmente presentes no charque, caracterizar parcialmente as bacteriocinas produzidas por essas culturas, avaliar seu potencial de aplicação neste produto para a melhoria de sua qualidade microbiológica e avaliar seu efeito na ecologia microbiana do charque, nas diferentes etapas de sua fabricação. Através da técnica de tripla camada em ágar foi isolada uma cepa de Lactococcus lactis subsp. lactis apresentando o gene codificador para nisina Z e com capacidade de inibir, in vitro, micro-organismos medianamente e altamente halotolerantes isolados de charque, além de outros micro-organismos deteriorantes e patogênicos importantes em alimentos, como Lactobacillus spp., Listeria monocytogenes e Staphylococcus aureus. A bacteriocina produzida pela cepa isolada neste estudo também possui características interessantes para sua aplicação na bioconservação de alimentos, como resistencia ao calor, presença de agente químicos e altos teores de NaCl, além de não ser afetada pelo pH. A aplicação dessa cepa em charque modelo resultou na redução de até 2 ciclos log na população de micro-organismos halotolerantes, indicando apresentar um potencial de aplicação como agente de bioconservação do produto. Os ensaios de avaliação da ecologia microbiana, empregando DGGE, indicaram que a fermentação natural do charque ocorreu com a participação de bactérias láticas dos gêneros Lactobacillus, Streptococcus, Lactococcus e de micro-organismos halotolerantes do gênero Staphylococcus. Além disso, os estudos referentes à dinâmica populacional demonstraram que a adição da cepa bacteriocinogênica ao charque não influenciou, de forma qualitativa, as populações presentes no produto

Charqui is a Brazilian traditional meat product, salted and sun-dried, still manufactured without control of the fermentation step, which is performed by the indigenous microbiota. This fact interferes on the standardization of the product and can negatively affect the sensorial properties and microbiological quality. The application of a known microbiota would be an alternative to minimize this problem and the bacteriocin-producing lactic acid bacteria can can fit in this purpose. The charqui indigenous microbiota mainly includes lactic acid bactéria and halophilic and halotolerant microorganisms, therefore, this product presents a potencial as a source for the isolation of new bacteriocin-producing lactic acid bacteria. The aim of the present work was to isolate and identify bacteriocin-producing lactic acid bacteria from charqui, characterize the bacteriocins produced by the isolated culture, evaluate its potential as biopreservative in charqui and its influence on the microbial populations during the manufacture of the product. A bacteriocinogenic Lactococcus lactis subsp. lactis strain was isolated from charqui through the triple-layer agar technique. This strain produces a nisin-like bacteriocin capable to inhibit in vitro medium and highly halotolerant bacteria isolated from charqui and other food-borne pathogenic and spoilage microorganisms. The application of this strain for charqui manufacturing caused a reduction of up to 2 log in the halotolerant bacteria population, evidencing its potential application for charqui biopreservation. Studies in the populational dynamics using DGGE indicated that the presence of the bacteriocinogenic strain did not affect the microbial populations in the product

Actividad antagonista de bacterias lácticas aisladas del medio marino contra cepas de Listeria / Antagonistic activity of lactic bacteria isolated from marine environment against Listeria strains / Atividade antagonista de bactérias lácticas isoladas do meio marinho contra cepas de Listeria

En el presente trabajo se estudiaron 74 bacterias lácticas para determinar su capacidad de inhibir el desarrollo de Listeria monocytogenes ATCC 7644 o L. innocua ATCC 33090. Dentro de las 7 que exhibieron actividad, 2 se seleccionaron para estudios complementarios y se identificaron por métodos fenotípicos y genotípicos como Enterococcus mundtii Tw 56 y Lactococcus lactis subsp. lactis Tw 34. Después de la neutralización con NaOH y tratamiento térmico (100 ºC y 121 ºC durante 5 min) la actividad antagonista del sobrenadante libre de células se mantuvo activa. El tratamiento con lisozima, lipasa y catalasa no afectó la actividad antimicrobiana. Sin embargo, la actividad enzimática de la tripsina suprimió la acción inhibitoria del sobrenadante, confirmando la naturaleza proteica del compuesto activo. En ambos casos, el título de la actividad antilisteria no se vio afectado luego de la inducción mediada por nisina o galactosa. La combinación de los sobrenadantes libres de células no exhibió antagonismo o sinergia. Las características bioquímicas y fisicoquímicas de los agentes antilisteria producidos por las cepas seleccionadas sugieren que pueden ser clasificadas como bacteriocinas tipo I o II. Se deben realizar estudios complementarios para determinar el uso potencial de las cepas seleccionadas como cultivos bioprotectores en el control de la seguridad alimentaria.

In the present work, 74 strains of lactic bacteria isolated from the marine environment were studied in order to determinate their ability to inhibit the growth of Listeria monocytogenes ATCC 7644 or L. innocua ATCC 33090. Among the 7 strains that exhibited some activity, 2 were selected for further studies and identified by phenotypic and genotypic methods as Enterococcus mundtii Tw 56 y Lactococcus lactis subsp. lactis Tw 34. After neutralization with NaOH and heat treatment (100 ºC and 121 ºC for 5 min) the antagonistic activity of cell-free supernatants of the two strains studied remained active. Treatment with lysozime, lipase and catalase did not affect the antimicrobial activity; however enzymatic activity of trypsin abolished the inhibitory action of the supernatant, confirming the proteinacious nature of the active compound. In both cases, the titre of antilisterial activity was not affected after nisin or galactose-mediated induction. The combination of cell-free supernatants of both strains did not display antagonism or synergy. The biochemical and physicochemical characteristics of antilisterial agents produced by the selected strains suggest that they can be classified as type I or II bacteriocins. Further studies will be adressed to determine the potential use of the selected strains as bioprotective cultures in food safety control.

No presente trabalho foram estudadas 74 bactérias lácticas para determinar sua capacidade de inibir o desenvolvimento de Listeria monocytogenes ATCC 7644 ou L. innocua ATCC 33090. Dentro das 7 que exibiram atividade, 2 foram selecionadas para estudos complementares e se identificaram por métodos fenotípicos e genotípicos como Enterococcus mundtii Tw 56 e Lactococcus lactis subsp. lactis Tw 34. Depois da neutralização com NaOH e tratamento térmico (100 ºC e 121 ºC durante 5 min) a atividade antagonista do sobrenadante livre de células se manteve ativa. O tratamento com lisozima, lipase e catalase não afetou a atividade antimicrobiana. Entretanto, a atividade enzimática da tripsina suprimiu a ação inibidora do sobrenadante, confirmando a natureza proteica do composto ativo. Em ambos os casos, o título da atividade antilisteria não se viu afetado depois da indução mediada por nisina ou galactose. A combinação dos sobrenadantes livres de células não exibiu antagonismo ou sinergia. As características bioquímicas e fisioquimicas dos agentes antilisteria produzidos pelas cepas selecionadas sugerem que podem ser classificadas como bacteriocinas tipo I ou II. Devem ser realizados estudos complementares para determinar o uso potencial das cepas selecionadas como culturas bioprotetoras no controle da segurança alimentar.

Resistência bacteriana e ação das bacteriocinas de Lactobacillus spp em Staphylococcus aureus isolados de mastite bovina / Bacterial resistance and bacteriocins action in Staphylococcus aureus isolated from bovine mastitis

Staphylococcus aureus is the major pathogen causing intramammary infections in dairy cattle worldwide. Among the factors that contribute to its spread and infectious potential is the ability to overcome the mechanisms of antimicrobials activity. The present work investigated the antimicrobial resistance pattern and sensibility to bacteriocins produced by strains of Lactobacillus spp of 30 isolates of S. aureus from mastitis. From this, 29 are beta-lactamase producers. Eight isolates (26.6 percent) showed resistance to at least four antibiotics being considered multiresistent. All of them were mecA-positive. Otherwise, all isolates tested showed sensibility to at least one of the four bacteriocin producer strains. Due to the significant depletion of the efficacy of antimicrobials, pathogen growth inhibition by bacteriocins seems an alternative of biological control in infectious processes.

Ação de bacteriocinas de bactérias láticas no controle de Listeria monocytogenes e no aumento da vida de prateleira de mortadela fatiada / Use of bacteriocins from lactic acid bacteria in the control of Listeria monocytogenes and in the shelf life extension of sliced mortadella

As bacteriocinas são peptídeos antimicrobianos produzidos por algumas bactérias, que atuam como bio-conservantes e têm grande potencial de aplicação em produtos cárneos. Estudos mostram que as bacteriocinas de bactérias lácticas (BAL) a serem utilizadas em um determinado alimento são mais eficientes quando produzidas por bactérias lácticas isoladas do mesmo tipo de alimento. Este estudo objetivou obter novas BAL produtoras de bacteriocinas a partir de mortadela fatiada, caracterizar as bacteriocinas produzidas, obter a bacteriocina semi-purificada e verificar seu potencial de aplicação in vitro e in situ no controle de Listeria monocytogenes e na vida de prateleira (VDP) de mortadela fatiada. Foram obtidos 19 isolados de BAL comprovadamente produtoras de bacteriocinas, que foram avaliadas quanto ao espectro de ação frente a uma grande variedade de bactérias Gram positivas e Gram negativas, e estabilidade em diferentes pH. As que apresentaram melhor estabilidade e inibiram maior número de bactérias foram avaliadas quanto a estabilidade térmica e resistência a diferentes agentes químicos e concentrações de NaCl. As que apresentaram maior resistência foram submetidas a testes de otimização da produção da bacteriocina em diferentes combinações de tempo/temperatura. Com base nestes resultados, selecionou-se um isolado que identificado como Lactobacillus curvatus pelo sequenciamento do gene 16S e confirmado por reações de PCR com primers específicos. A bacteriocina produzida por este isolado foi submetida a uma purificação por extração ácida e aplicada em fatias de mortadela experimentalmente contaminadas com um pool de cepas de Listeria monocytogenes, observando-se as contagens deste patógeno durante o armazenamento em refrigeração (7°C) por 40 dias em embalagem à vácuo. Paralelamente, foi realizada contagem de bactérias láticas para avaliar o efeito da bacteriocina nesta população, responsável pela VDP deste produto. A bacteriocina parcialmente purificada foi ...

Bacteriocins are peptides with antimicrobial properties produced by some bacteria, that act as bio-preservatives with great potential of application in meat products. Several studies show that bacteriocins from lactic acid bacteria (LAB) to be used in a specific food product have a better performance when produced by LAB isolated from the same kind of product. This study aimed to obtain new bacteriocinogenic LAB from sliced Bologna, to characterize the bacteriocins produced, to obtain a semi-purified bacteriocin, and to verify its potential of application in vitro and in situ in the control of Listeria monocytogenes and in the shelf-life of sliced bologna. 19 bacteriocin producer LAB, were evaluated as to spectrum of action against a great variety of Gram positives and Gram negatives bacteria and pH stability. The ones with better stability and that inhibited a larger number of bacteria were evaluated according to its thermal stability and resistance against different chemical agents and NaCl concentrations. The ones that showed better resistance were submitted to tests to optimize the bacteriocin production in different combinations of time and temperature. Based on these results, one was selected, identified as Lactobacillus curvatus by gene 16S sequencing and confirmed by PCR reactions with specific primers. The bacteriocin produced by this strain was submitted to partial purification by acid extraction and was applied in mortadella slices experimentally contaminated with a pool of L. monocytogenes strains, observing the counts of this pathogen along refrigerated (7ºC) storage fo r 40 days in vacuum package. Parallel, it was done LAB counts to evaluate the effect of the bacteriocin on this population, responsible for limiting the shelf life of this product. The semi-purified bacteriocin was able to reduce 1 log cicle of the initial population of L. monocytogenes in the sliced mortadella, which was maintained during the 40 days of analysis. Along the whole...

Immuno-enhancing Effects of Lactobacillus salivarius JWS 58 and Lactobacillus plantarum JWS 1354 isolated from duck / 대한수의학회지

Lactobacillus salivarius JWS 58 (JWS 58) and Lactobacillus plantarum JWS 1354 (JWS 1354) are isolated from duck intestine and have ability to produce bacteriocin. The objective of this study was to evaluate the immunomodulatory effects of JWS 58 and JWS 1354. The nitric oxide (NO) and cytokines (IL-1beta and TNF-alpha) were measured in C57BL/6 mouse peritoneal macrophages to determine immune enhancing effects of JWS 58 and JWS 1354. A Listeria (L.) monocytogenes challenge mice model was used to evaluate immune enhancement ability of JWS 58 and JWS 1354 in vivo. The results showed that JWS 58 and JWS 1354 increased the production of NO or cytokines by peritoneal macrophages and that oral administration of viable probiotic strains in mice elicited the immuno-modulatory effect upon L. monocytogenes challenge. JWS 1354 showed stronger immune enhancing effects than JWS 58. Collectively, this study demonstrated that Lactobacillus strain JWS 58 and JWS 1354 possess immune enhancing effect. Furthermore, two stains are expected to use feed supplement to prevent diseases by pathogenic bacteria through releasing bacteriocin and enhancing host immune responses in animal.

Comparative antimicrobial activity of two new mutacins / Actividad microbiana comparativa de dos nuevas mutacinas

OBJECTIVES: To compare the in vitro activity of mutacins D-123.1 and F-59.1 against different bacteria including antibiotic-resistant strains, in order to evaluate their application potential. DESIGN AND METHODS: The antibacterial activity spectrum of purified F-59.1 and the MIC and MBC of F-59.1 and D-123.1 against target bacteria were determined. RESULTS: Most bacteria were inhibited by the purified mutacins. Mutacin F-59.1 shows a relatively wide activity spectrum. Mutacin D-123.1 has low Minimum Inhibitory Concentrations [MICs] (0.25-4 µ/ml) against human pathogens while F-59.1 has higher MICs (3.2-12.8 fig/ml) mainly against food-borne pathogens. CONCLUSION: The effectiveness of mutacins D-123.1 and F-59.1 against human and food-borne pathogens is demonstrated. Mutacin D-123.1 shows potential as a new antibiotic while F-59.1 shows promising application in food products. ABBREVIATIONS: MALDI-TOF MS, matrix assisted laser desorption ionisation-time of flight mass spectrometry; MB(I)C, minimum bactericidal (inhibitory) concentrations; OD, optical density; RP-HPLC, reverse-phase high-pressure liquid chromatography; TSBYE, trypticase soy broth yeast extract.

OBJETIVOS: Comparar la actividad in vitro de las mutacinas D-123.1 y F-59.1 frente a diferentes bacterias incluyendo las cepas resistentes a los antibióticos, a fin de evaluar el potencial de su aplicación. DISEÑO Y MÉTODOS: Se determinó el espectro de actividad antibacteriana de F-59.1 purificada y la CIM y la CBM de F-59.1 y D-123.1 frente a determinadas bacterias. RESULTADOS: La mayor parte de las bacterias eran inhibidas por las mutacinas purificadas. La mutacina F-59.1 muestra un espectro de actividad relativamente amplio. La mutacina D-123.1 posee bajas concentraciones de inhibición mínimas [CIM] (0.25-4 fig/ml) contra los patógenos humanos, mientras que el F-59.1 posee concentraciones CIM más altas (3.2-12.8 fig/ml) principalmente frente a los patógenos alimentarios. CONCLUSIÓN: Queda demostrada la efectividad de las mutacinas D-123.1 y F-59.1 frente a los patógenos humanos y alimentarios. La mutacina D-123.1 muestra poseer un potencial como nuevo antibiótico, en tanto que F-59.1 se presenta como una aplicación promisoria en relación con los productos alimentarios. ABREVIATURAS: MALDI-TOF MS, espectrometría de masas con desorción/ionización mediante láser asistida por matriz asociada a un analizador de tiempo de vuelo (del inglés: matrix assisted laser desorption ionisation-time de flight mass spectrometry). CIM: concentración inhibitoria mínima (inglés MIC). CBM: concentración bactericida mínima (inglés MBC). DO: densidad óptica (inglés OD); RP-HPLC: cromatografía líquida de alta resolución en fase revertida; TSBYE:caldo tripticasa soya- extracto de levadura.