Injúria microbiana e a qualidade microbiológica dos alimentos / Microbial injury and the microbiological quality of food

Introdução: a contaminação microbiológica dos alimentos se apresenta como um grande problema para a indústria, agências reguladoras e consumidores. Os métodos de conservação utilizados como garantia da inocuidade dos alimentos bem como de extensão da vida de prateleira garantem uma redução significativa do número de células viáveis e/esporos. Entretanto, em virtude da aplicação de técnicas como calor, frio, redução da atividade de água e adição de conservantes, parte da população microbiana pode apresentar células com danos letais bem como danos reversíveis, tornando-se injuriadas. Objetivo: realizar uma revisão bibliográfica acerca da ocorrência de injúrias microbianas decorrentes da aplicação de métodos de conservação em alimentos. Metodologia: consulta das bases de dados Pubmed e Scielo, com seleção de artigos publicados entre os anos de 2000 e 2019. Revisão de literatura: os microrganismos se tornam injuriados após sobreviverem a condições estressantes e perderem parte de suas características funcionais, o que justifica um maior período para multiplicação nos alimentos, assim como em meios de cultura tradicionais. Cabe ressaltar que, caso estes microrganismos sejam expostos à ambientes favoráveis, é possível a recuperação dos danos sofridos. Uma vez regenerados, estes agentes representam um perigo potencial, visto a capacidade de se multiplicarem novamente no alimento, oferecendo riscos aos consumidores e acelerando a deterioração de produtos alimentícios. Conclusão: diante da ocorrência de injúrias microbianas, percebe-se a necessidade de incorporação de procedimentos adequados para recuperação de danos celulares aos métodos oficiais empregados para detecção e enumeração de microrganismos, a fim de garantir a qualidade e inocuidade de alimentos.

Introduction: Microbiological contamination of food is a major problem for industry, regulatory agencies and consumers. Preservation methods used to guarantee the safety of food as well as extending the shelf life ensure a significant reduction in the number of viable cells and/or spores. However, due to the application of techniques such as heat, cold, reduction of water activity and addition of preservatives, part of the microbial population may present cells with lethal damage as well as reversible damage, becoming injured. Objective: to carry out a literature review about the occurrence of microbial injuries resulting from the application of preservation methods in food. Methodology: pubmed and Scielo databases were consulted, with a selection of articles published between 2000 and 2019. Literature review: microorganisms become injured after surviving stressful conditions and losing part of their functional characteristics, which justifies a longer period for multiplication in food, as well as in traditional culture media. It should be noted that, if these microorganisms are exposed to favourable environments, it is possible to recover from the damage suffered. Once regenerated, these agents represent a potential hazard, given their ability to multiply again in food, posing risks to consumers and accelerating the deterioration of food products. Conclusion: in view of the occurrence of microbial injuries, it is necessary to incorporate adequate cell damage recovery procedures to the official methods used for detection and enumeration of microorganisms, in order to guarantee the quality and safety of food.

Análise microbiológica de sushi comercializado em Rio Branco, Acre / Microbiological analysis of sushi marketed in Rio Branco, Acre / Análisis microbiológico de sushi comercializado en Rio Branco, Acre

O Brasil é um dos países mais diversificados no ramo gastronômico oferecendo vários alimentos diferentes aos seus consumidores, com base nos próprios pratos típicos ou provenientes de outras culturas. O pescado trata-se de um alimento perecível que necessita de atenções especiais em seu processamento. Falhas nas condições higiênico-sanitárias, associadas com a não cocção do alimento, podem ocasionar em uma contaminação e proliferação de bactérias, o que leva à uma grande preocupação a nível de saúde pública. O estudo analisou os aspectos microbiológicos de sushi comercializado na cidade de Rio Branco ­ Acre verificando os parâmetros de qualidade e as condições higiênicas sanitárias, comparando os resultados obtidos com a legislação vigente estabelecida pela ANVISA. Foram escolhidos 5 estabelecimentos aleatoriamente, sendo escolhidas 3 amostras de sushis do tipo niguiri de cada. As análises microbiológicas incluíram coliformes totais e coliformes termotolerantes utilizando a técnica dos tubos multiplos e a técnica de semeadura por profundidade para mesófilos e Salmonella. Constatou-se que todas as amostras tiveram um crescimento bacteriano e presença sugestiva de Salmonella, tornando o alimento impróprio para o consumo e mostrando uma falha nas condições higiênico- sanitária ao qual o sushi é processado e armazenado. É necessário maior fiscalização dos órgãos responsáveis e cuidado dos estabelecimentos que vendem sushi na cidade de Rio Branco, para que o produto vendido seja de boa qualidade e não cause malefícios a saúde de quem o consome.(AU)

Brazil is one of the most diversified countries in the gastronomic field, offering several different foods to its consumers, based on typical dishes or from other cultures. Fish is a perishable food that requires special attention in its processing. Failures in hygienic-sanitary conditions, coupled with the consumption of undercooked food, can lead to contamination and the proliferation of bacteria, which raises significant concerns regarding public health. The study analyzed the microbiological aspects of sushi sold in the city of Rio Branco - Acre, verifying the quality parameters and the hygienic sanitary conditions, comparing the obtained results with the current legislation established by ANVISA. Five establishments were randomly selected, and three samples of nigiri sushi were chosen from each establishment. The microbiological analysis included total coliforms and thermotolerant coliforms using the multiple tube technique, as well as depth seeding technique for mesophiles and Salmonella. It was found that all samples exhibited bacterial growth and suggested the presence of Salmonella, rendering the food unsuitable for consumption and indicating a failure in the hygienic-sanitary conditions under which the sushi was processed and stored. Greater inspection by the responsible authorities and improved care by establishments selling sushi in the city of Rio Branco are necessary to ensure that the product sold is of good quality and does not pose harm to the health of consumers.(AU)

Brasil es uno de los países más diversificados en el campo gastronómico, ofreciendo muchos alimentos diferentes a sus consumidores, basados en platos típicos ode otras culturas El pescado es un alimento perecedero que necesita especial atención en su elaboración. Las fallas en las condiciones, higiénico-sanitarias asociadas a la no cocción de los alimentos, pueden conducir a la contaminación y proliferación de bacterias, lo que genera una gran preocupación en términos de salud pública. El estudio analizó los aspectos microbiológicos del sushi comercializado en la ciudad de Rio Branco - Acre, verificando los parámetros de calidad y las condiciones higiénicas sanitarias, comparando los resultados obtenidos con la legislación vigente establecida por la ANVISA. Se eligieron 5 establecimientos al azar, y de cada uno se escogieron 3 muestras de sushi niguiri. Los análisis microbiológicos incluyeron coliformes totales y coliformes termotolerantes mediante la técnica de tubos múltiples y la técnica de siembra profunda para mesófilos y Salmonella. Se encontró que todas las muestras presentaban crecimiento bacteriano y la sugestiva presencia de Salmonella, lo que hace que el alimento no sea apto para el consumo y presenta una falla en las condiciones higiénico-sanitarias en las que se procesa y almacena el sushi. Se necesita mayor fiscalización por parte de los órganos responsables y cuidado de los establecimientos que venden sushi en la ciudad de Rio Branco, para que el producto vendido sea de buena calidad y no cause daño a la salud de quien lo consume.(AU)

Compliance in handling of donated raw breast milk to human milk banks regarding microbiological quality / Conformidade no manuseio do leite materno cru doado aos bancos de leite humano em relação à qualidade microbiológica

Abstract Objectives: microbiological quality of raw human milk (HM) from donors at the HMB (Human Milk Bank) of Santa Casa de Misericórdia de Ouro Preto was evaluated. Methods: the microbiological quality of milk from each of 10 donors in triplicate (30 samples) was evaluated by enumeration of Staphylococcus aureus and total aerobic mesophiles (surface plating) and total and thermotolerant coliforms (Most Probable Number - MPN). A questionnaire and a checklist were applied after the end of sample collection to verify the compliance of milk extraction and storage procedures by the donors. Results: inadequacies in the procedures for expression and storage of donated HM were observed. The presence of all microorganisms studied were verified in the milk of all donors, and in some cases exceeded the safety limits. The checklist indicated that some necessary hygienic-sanitary procedures were not carefully performed, making it important to properly guide the donors. Conclusions: this study points to an unfavorable scenario for the safety and quality of donated HM, and it is important to encourage further studies to be conducted so that the Brazilian network of HMB adopts stricter criteria for instructions on procedures and support for HM donors.

Resumo Objetivos: avaliou-se a qualidade microbiológica do leite humano (LH) cru de doadoras do Banco de Leite Humano (BLH) da Santa Casa de Misericórdia de Ouro Preto. Métodos: a qualidade microbiológica do leite de cada uma das 10 doadoras em triplicata (30 amostras) foi avaliada por meio da enumeração de Staphylococcus aureus e mesóflos aeróbios totais (plaqueamento em superfície) e coliformes totais e termotolerantes (Número Mais Provável -NMP). Para verificar a conformidade dos procedimentos de extração e armazenamento do leite pelas doadoras, aplicou-se um questionário e um checklist após o término da coleta das amostras. Resultados: observou-se inadequações nos procedimentos de expressão e armazenamento do LH doado. A presença de todos os microrganismos estudados foram verificados no leite de todas as doadoras e, em alguns casos, excedeu os limites de segurança. O checklist indicou que alguns procedimentos higiênico-sanitários necessários não foram realizados criteriosamente, tornando importante orientar adequadamente as doadoras. Conclusões: este estudo aponta um cenário desfavorável para a segurança e a qualidade do LH doado, sendo importante incentivar mais estudos a serem realizados para que a rede brasileira de BLH adote critérios mais rigorosos de instruções sobre procedimentos e suporte para doadoras de LH.

Calidad microbiológica, satisfacción laboral y de clientes en una empresa fast food, Arequipa / Microbiological quality, job and customer satisfaction in a fast food company, Arequipa

"Fast food" es un fenómeno económico que crece con ritmo acelerado en el mercado peruano, estos deben contar con alimentos seguros de ingesta y personal satisfecho que dé cumplimiento a las normativas higiénicas. Como objetivo, se propuso determinar la calidad microbiológica y satisfacción laboral en una empresa fast food, Arequipa, 2022, cuya muestra fue de 384 trabajadores distribuidos en 11 franquicia. Para la recolección de datos se realizaron tres actividades, 1) la aplicación de un cuestionario de 21 ítems la percepción de los trabajadores sobre las buenas prácticas y el cuidado de los alimentos, 3) la valoración microbiológica de las materias primas que ingresan a la empresa y 3) la valoración de la percepción de los trabajadores de la calidad y la satisfacción laboral. El análisis de datos se hizo mediante estadística descriptiva a través del paquete estadístico SPSS con aplicación de Kolmogorov-Smirnov y Rho de Spearman para la correlacion entre la calidad y la satisfacción laboral. Como resultado, 81,51% en el aseo personal, 79,69% aseo diario, 78,91% prohibición de hábitos nocivos, 77,34% uso del uniforme y EPP y 50,78% limpieza de las manos, catalogándose como "muy buenas", el análisis microbiológico se encontró 35 UFC/ml de coliformes fecales y 31 UFC/ml de coliformes totales con 4 UFC/ml exarcebado en el agua. La satisfacción laboral fue "bueno" en la totalidad de las variables, las pruebas de normalidad fueron menor a <0,05, con un Rho de Spearman de 0,611, aceptándose la hipótesis alterna y rechazando la nula(AU)

"Fast food" is an economic phenomenon that is growing rapidly in the Peruvian market, these must have safe food to eat and satisfied staff that comply with hygienic regulations. As an objective, it was proposed to determine the microbiological quality and job satisfaction in a fast food company, Arequipa, 2022, whose sample was 384 workers distributed in 11 franchises. For the data collection, three activities were carried out, 1) the application of a 21-item questionnaire, the perception of workers about good practices and food care, 3) the microbiological evaluation of the raw materials that enter the company. and 3) the assessment of workers' perception of quality and job satisfaction. Data analysis was done using descriptive statistics through the SPSS statistical package with the application of Kolmogorov-Smirnov and Spearman's Rho for the correlation between quality and job satisfaction. As a result, 81.51% in personal hygiene, 79.69% daily hygiene, 78.91% prohibition of harmful habits, 77.34% use of uniform and PPE and 50.78% hand cleaning, being classified as " very good", the microbiological analysis found 35 CFU/ml of fecal coliforms and 31 CFU/ml of total coliforms with 4 CFU/ml exacerbated in the water. Job satisfaction was "good" in all the variables, the normality tests were less than <0.05, with a Spearman's Rho of 0.611, accepting the alternate hypothesis and rejecting the null(AU)

Potentially pathogenic Staphylococcus aureus and Listeria spp. in Brazilian unpasteurized cheese production / Staphylococcus aureus e Listeria spp. potencialmente patogênicos na produção de queijos não pasteurizados

This study aimed to identify potentially pathogenic microorganisms (Listeria innocua, L. seeligeri, L. ivanovii, L. monocytogenes, Staphylococcus aureus, and several virulence genes) in unpasteurized cheese production in the northeastern region of the state of São Paulo, Brazil. Listeria species were detected in 68 (64.14%) out of 106 samples of bovine feces, swabs from milkers' and cheese handlers' hands, milking buckets, raw milk, whey, water, cheese processing surface,s and utensils. All the samples collected at one farm were contaminated with Listeria spp. L. innocua, L. seeligeri, L. ivanovii, or L. monocytogenes were not detected in the samples collected in this study. A set of 391 Staphylococcus spp. isolates were obtained in these samples, from which 60 (15.31%) were identified as S. aureus using PCR (Polymerase Chain Reaction). S. aureus carrying virulence genes (eta, hlg, seg, seh, sei) were detected in milk, in swabs from cheese handler's hands, whey, milk, sieves, buckets, and cheese. The hlg gene (encodes gamma hemolysin) was detected in all the S. aureus isolates. These findings show that poor hygienic practice is associated with a higher risk of pathogenic bacteria in milk or cheese, providing useful information for public health authorities to increase food safety surveillance and prevent the dissemination of pathogens.

O objetivo desse estudo foi identificar microrganismos potencialmente patogênicos (Listeria innocua, L. seeligeri, L. ivanovii, L. monocytogenes, Staphylococcus aureus e diversos genes de virulência) na produção de queijos de leite cru na região noroeste do Estado de São Paulo, Brasil. Listeria foram detectadas em 68 (64,14%) das 106 amostras obtidas de fezes bovinas, suabes das mãos de ordenhadores e queijeiros, baldes, leite cru, soro, água, superfícies e utensílios da produção de queijos. Todas as amostras coletadas em uma fazenda estavam contaminadas com Listeria spp. L. innocua, L. seeligeri, L. ivanovii, e L. monocytogenes não foram detectadas nas amostras coletadas nesse estudo. Um conjunto de 391 isolados de Staphylococcus spp. foram obtidos das amostras, e desses 60 (15,31%) foram identificados como S. aureus pela PCR (Polymerase Chain Reaction). S. aureus contendo genes de virulência (eta, hlg, seg, seh, sei) foram detectados em leite, mãos dos ordenhadores, soro, utensílios e queijos. O gene hlg (gama-hemolisina)foi detectado em todos os isolados de S. aureus.Esses resultados demonstram que práticas inadequadas de higiene estão associadas com um maior risco da presença de bactérias patogênicas no leite e queijos crus, fornecendo informações para as autoridades de saúde pública para incrementarem a vigilância e prevenirem a disseminação de patógenos.

Evaluación de la resistencia a los antibióticos de cepas de Escherichia coli aisladas en carne de cerdo comercializada en los mercados municipales de la ciudad de Guatemala / Evaluation of antibiotics resistance of Escherichia coli strains isolated in pork sold in municipal markets of Guatemala City

La resistencia a los antimicrobianos es un problema de salud pública a nivel mundial que va en aumento y se ve reflejada en la falta de eficacia de los tratamientos de infecciones bacterianas con antibióticos en humanos y en animales. El presente estudio tuvo como objetivo evaluar la resistencia a los antibióticos de cepas de Escherichia coli aisladas en carne de cerdo expendida en los mercados municipales de la ciudad de Guatemala. Se identificaron los antibióticos que presentaron mayor resistencia y mayor sensibilidad in vitro frente a las cepas de E. coli aisladas a partir de 76 muestras de carne de cerdo. Se realizó un muestreo aleatorio simple con afijación proporcional por mercado. Para la identificación de las cepas de E. coli se utilizó la prueba de IMViC y para evaluar la resistencia a los antimicrobianos se utilizó la prueba de Kirby Bauer empleando 9 antibióticos. Se aisló E. coli en el 55% (42/76) de las muestras. La resistencia en las 42 cepas aisladas fue: tetraciclina (83%) neomicina (50%) y sulfametoxasole + trimetoprim (50%). 83% de las cepas (35/42) fueron resistentes a 2 antibióticos y 50% (21/42) a 3 antibióticos o más. Se obtuvo mayor sensibilidad con ceftriaxona (91%), amikacina (83%), gentamicina (65%) y ácido nalidíxico (65%). Se concluye que existe resistencia a los antibióticos evaluados, lo que constituye un riesgo para la salud pública ya que se encuentra en cepas aisladas en un alimento para consumo humano.

Antimicrobial resistance is a global public health threat that is increasing and is reflected in the lack of efficacy of bacterial infection treatments with antibiotics in humans and animals. The objective of this study was to evaluate the resistance to antibiotics of Escherichia coli strains isolated from pork in the municipal markets of Guatemala City. Antibiotics with the highest resistance and those with the highest sensitivity in vitro against the strains of E. coli were evaluated. A simple random sampling was carried out with proportional allocation by market, and 76 samples were collected. IMViC test was used to identify the E. coli strains, and antibiotics resistance was evaluated using the Kirby Bauer with nine different antibiotics. E. coli was isolated in 55% (42/76) of the samples. Resistance was evaluated in the 42 isolates. Antibiotic resistance was detected to tetracycline (83%), neomycin (50%), and sulfamethoxazole + trimethoprim (50%). All isolates presented resistance to at least one antibiotic; it was determined that 83% (35/42) showed resistance to two antibiotics and 50% (21/42) showed resistance to three antibiotics or more. The sensitivity obtained was higher for ceftriaxone (91%), amikacin (83%), gentamicin (65%), and nalidixic acid (65%). In conclusion, antibiotic resistance was detected, which constitutes a risk to public health since it is found in isolated strains in food for human consumption.

Alterantes microbianos atípicos en yogures argentinos: mohos gasógenos y bacterias del género Gluconobacter / Atypical spoilage microorganisms in Argentinean yogurts: Gas-producing molds and bacteria of the genus Gluconobacter

RESUMEN El deterioro microbiológico de alimentos conduce a productos no aptos para consumo, y su descarte, a importantes pérdidas económicas para la industria alimenticia. Durante su almacenamiento, los alimentos frescos representan nichos atractivos para la supervivencia y el crecimiento de microorganismos indeseables. En productos lácteos, la presencia de alterantes o patógenos bacterianos está mejor documentada que la de mohos y levaduras. Estos productos son menos proclives al deterioro por mohos que otros, como frutas y verduras, debido a su almacenamiento refrigerado, su elaboración a partir de leche tratada térmicamente y, para fermentados, a la microbiota dominante, que acidifica el medio. Sin embargo, incluso quesos y yogures pueden sufrir deterioro por mohos. Este trabajo presenta casos atípicos de muestras de yogur con desarrollo de mohos gasógenos y bacterias del géneroGluconobactercomo microorganismos alterantes no reportados previamente como tales en leches fermentadas argentinas. Los organismos alterantes «clásicos¼ de yogur fueron siempre levaduras y, en otros países, mohos del géneroAspergillus.

ABSTRACT Microbial food alterations lead to unfit products for consumption, and their discarding, to significant economic losses for the food industry. During storage, fresh foods offer available niches for the survival and growth of undesirable microorganisms. In dairy products, data regarding spoilage and/or pathogenic bacteria is better documented than those for molds and yeasts. Dairy products are less susceptible to mold's contamination than products such as fruits and vegetables, due to their refrigerated storage; their elaboration from heat-treated milk and, for fermented ones, the dominant microbiota that acidifies the medium. However, even cheeses and yogurts may be susceptible to mold contamination. Atypical cases of yogurt samples containing spoilage microorganisms not previously reported (molds producing gas and bacteria of the genusGluconobacter) in Argentinean fermented milks are presented here. For yogurt, in particular, the "classic" altering organisms were always being yeasts, and in other countries, molds belonging to the genusAspergillus.

Immunological and biossensory techniques for detection of Salmonella spp. in food derived from fish farming- review / Técnicas imunológicas e biossensoriais para detecção de Salmonella spp. em alimentos derivados da piscicultura ­ revisão de literatura / Técnicas inmunológicas y biosensoriales para detección de Salmonella spp. en alimentos derivados de piscicultura - revisión de literatura

Salmonellosis is the world's most common foodborne illness. In Brazil, foods contaminated by salmonella lead the statistics. Therefore, the aim of this study is, through biotechnological knowledge, to compile alternative and innovative techniques for the detection of salmonella in foods, such as fish-farming derivatives, immunological and biosensorial techniques. This is a descriptive exploratory data survey of a qualitative nature, aiming at data analysis. Research and data collection were carried out in bibliographic databases: Academic Google, Scielo, CAPES journals and institutional repositories using specific descriptors - in Portuguese and English, with words and terms separated by the Boolean operators 'AND' and 'OR'. Some innovative and alternative methods are available to identify the presence of salmonella in food. Immunological and biosensory techniques, despite being less frequent in the scientific literature than molecular methods, are techniques that present high specificity and sensitivity. These techniques have been the most developed alternative methods in fish in recent years. And, they can employ both molecular and immunological techniques in biorecognition, which is characterized as an advantage of not having a requirement for pre-enrichment of the sample. According to the literature found, the techniques covered in this study are quick to respond, which speeds up decision-making by researchers and technicians, which makes the techniques very promising for industrial application.(AU)

A salmonelose é uma enfermidade de maior ocorrência no mundo veiculada por alimentos. No Brasil, alimentos contaminados por salmonelas lideram as estatísticas. Por isso, o objetivo desse estudo é através dos conhecimentos biotecnológicos compilar técnicas alternativas e inovadoras para a detecção de salmonelas em alimentos, como os derivados da piscicultura, as técnicas imunológicas e biossensoriais. Trata-se de um estudo de levantamento de dados descritivo exploratório de de caráter qualitativo, visando à análise dos dados. As pesquisas e coletas de dados foram realizadas nas bases bibliográficas: Google Acadêmico, Scielo, periódicos da CAPES e repositórios institucionais utilizando os descritores específicos - nos idiomas português e inglês, com palavras e termos separados pelos operadores booleanos 'AND' e 'OR'. São disponibilizados alguns métodos inovadores e alternativos para identificação da presença de salmonelas em alimentos. As técnicas imunológicas e biossensoriais, apesar de serem menos frequentes na literatura científica do que os métodos moleculares são técnicas que apresentaram elevada especificidade e sensibilidade. Essas técnicas têm sido os métodos alternativos mais desenvolvidos em peixes nos últimos anos. E, podem empregar tanto técnicas moleculares como imunológicas no biorreconhecimento, o que se caracteriza como vantagem de não haver requerimento de pré-enriquecimento da amostra. Conforme a literatura encontrada, as técnicas abordadas por esse estudo apresentam rapidez de resposta o que agiliza as tomadas de decisões dos pesquisadores e técnicos, o que torna as técnicas bastante promissora para aplicação industrial.(AU)

La salmonelosis es la enfermedad transmitida por alimentos más común del mundo. En Brasil, los alimentos contaminados por salmonelas lideran las estadísticas. Por tanto, el objetivo de ese estudio fue a través de conocimientos biotecnológicos recopilar técnicas alternativas e innovadoras para la detección de salmonelas en los alimentos, como los derivados de la piscicultura, las técnicas inmunológicas y biosensoriales. Se trata de una encuesta de datos exploratorio descriptivo de carácter cualitativo, cuyo objetivo es el análisis de datos. Las investigaciones y recopilaciones de datos se realizaron en bases de datos bibliográficas: Google Académico, Scielo, revistas CAPES y repositorios institucionales utilizando descriptores específicos, en portugués e inglés, con palabras y términos separados por los operadores booleanos 'AND' y 'OR'. Se encuentran disponibles algunos métodos innovadores y alternativos para identificar la presencia de salmonela en los alimentos. Las técnicas inmunológicas y biosensoriales, a pesar de ser menos frecuentes en la literatura científica que los métodos moleculares, son técnicas de alta especificidad y sensibilidad. Esas técnicas han sido los métodos alternativos más desarrollados en peces en los últimos años. Y pueden emplear técnicas tanto moleculares como inmunológicas en el biorreconocimiento, que se caracteriza por la ventaja de no tener un requisito de preenriquecimiento de la muestra. Según la literatura encontrada, las técnicas abordadas en este estudio son de rápida respuesta, lo que agiliza la toma de decisiones por parte de investigadores y técnicos, lo que hace que las técnicas sean muy prometedoras para la aplicación industrial.(AU)

Análise microbiológica de morangos frescos comercializados em Goiânia, Goiás / Microbiological analysis of fresh strawberries comercialized in Goiânia, Goiás

Objetivo: O consumo de alimentos contaminados por microrganismos patogênicos pode levar a quadros de doenças transmitidas por alimentos. O presente estudo objetivou realizar uma análise microbiológica de morangos frescos (Fragaria vesca) comercializados em Goiânia, Goiás, pesquisando a presença de Escherichia coli e Salmonella spp., em consonância com a RDC nº 12, de 02 de janeiro de 2001. Métodos: Foram analisadas 51 amostras de morangos frescos in natura no Laboratório Clínico da PUC Goiás, sendo 25 amostras oriundas de supermercados e 26 de comércio livre/rua, entre agosto/2019 e dezembro/2019, em diversos bairros das regiões Norte, Noroeste, Sul e Central do município de Goiânia, Goiás. Foram feitas culturas bacterianas nos ágares Eosin Methylene Blue e Salmonella-Shigella, e identificados os isolados por provas bioquímicas clássicas. Como controle de qualidade, a cada bateria de experimentos, duas cepas bacterianas conhecidas, uma Salmonella spp. (Programa Nacional de Controle de Qualidade/PNCQ) e uma E. coli ATCC 25923, foram utilizadas. Resultados: Das 51 amostras analisadas, 5,9% (3/51) apresentaram positividade para o crescimento de E. coli, sendo estas amostras adquiridas no comércio livre/rua. Foi observada ausência de Salmonella spp. Conclusão: A grande maioria (94,1%) das amostras analisadas nesta pesquisa negativaram em relação à presença de E. coli e 100% negativaram para a presença de Salmonella spp., demonstrando que independente de adquiridos em comércio livre/rua ou em supermercados, os morangos encontravam-se microbiologicamente seguros para o consumo, de acordo com a legislação brasileira vigente.

Objective: The consumption of food contaminated by pathogenic microorganisms can cause Foodborne Diseases. The present study aimed to perform a microbiological analysis of fresh strawberries (Fragaria vesca) marketed in Goiânia, Goiás, researching the presence of Escherichia coli and Salmonella spp., in line with RDC No. 12, of January 2, 2001. Methods: They have analyzed 51 samples of fresh strawberries in natura at the Clinical Laboratory of PUC Goiás, 25 samples from supermarkets and 26 from free trade/street, between August/2019 and December/2019, in several neighborhoods in the North, Northwest, South, and Central regions county of Goiânia, Goiás. Bacterial cultures cultivated on Eosin Methylene Blue and Salmonella-Shigella agar, and identification of the isolates by standard biochemical tests. As a quality control, in each battery of experiments, two known bacterial strains, one Salmonella spp. (National Quality Control Program/PNCQ) and an E. coli ATCC 25923 was used. Results: Of the 51 samples analyzed, 5.9% (3/51) were positive for the growth of E. coli, these samples were acquired in free/street commerce. Absence of Salmonella spp. Conclusion: The majority (94.1%) of the samples analyzed in this research were negative concerning the presence of E. coli, and 100% were negative for the presence of Salmonella spp., demonstrating that independent of being acquired in free trade/street or supermarkets, the strawberries analyzed were microbiologically safe for consumption, following the current Brazilian legislation.

Evaluation of physic contamiants and contamination with coliforms, molds and yeasts of honey from the Northern Brazil / Avaliação de contaminantes físicos e contaminação com coliformes, bolores e leveduras de mel do Norte do Brasil

The Mercosur Technical Regulation for honey determines microbiological parameters for total coliforms and molds and/ yeasts, and absence of physical contaminants, of any nature. The purpose of this study was to verify the biological and physical contamin of Apis mellifera ligustica and Melipona fasciculata, commercialized in the northeastern region of the State of Pará, Brazil. The fourteen samples from informal trade of the municipalities of Bragança, Capanema, Nova Timboteua, São João de Pirabas, Salinas and Tracauateua were analyzed for the Most Probable Number of colifroms at 35ºC, Fungus and Yeast counts, besides the detection of dirt by Macro and Microscopy techniques. The results obtained from the microbiological analyzes were compared to the standard required by MERCOSUR, for coliforms. 57.14% of the samples were non-standard and ranged from <3.0 NMP/g to 20 NMP/g. The molds and/ yeast counts ranged from 1x10¹ CFU/g to 8.6x10² CFU/g, with atotal of 21.42% of the samples being in disagreement with the legislation. From the macroscopic analysis, it was observed that, although 50% of the samples did not present any apparent dirt, microscopically it was possible to observe dirt in 100% of the samples of honey analyzed, which is out of the standard required by the Brazilian legislation. This shows the low sanitary quality of honey commercialized in this region of the state of Pará.

O Regulamento Técnico do Mercosul para mel, determina parâmetros microbiológicos para coliformes totais e fungos e/leveduras, e ausência de contaminantes físicos, de qualquer natureza. A proposta do presente estudo foi verificar a contaminação biológica e física em méis de abelha das espécies Apis mellifera ligustica e Melipona fasciculata, comercializados na região Nordeste do Estado do Pará, Brasil. As amostras provenientes do comercio informal dos de municípios de, Bragança, Capanema, Nova Timboteua, São João de Pirabas, Salinas e Tracauateua, foram analisadas quanto a determinação do Número Mais Provável de coliformes a 35ºC, Contagem de Fungos e/leveduras, além da detecção de sujidades pelas técnicas de Macro e Microscopia. Os resultados obtidos a partir das análises microbiológicas foram comparadas ao padrão exigido pelo MERCOSUL, para coliformes, 57,14% das amostras encontravam-se fora do padrão variaram de <3,0 NMP/g a 20NMP/g. Já a contagem de fungos e/leveduras variou de 1x10¹ UFC/g a 8,6x10² UFC/g, no total de 21,42 % das amostras apresentaram-se em desacordo com a legislação. A partir da análise macroscópica observou-se que, embora 50% das amostras não apresentassem sujidades aparentes, porém microscopicamente foi possível observar a presença sujidades em 100% das amostras de méis analisadas encontrando-se fora do padrão exigido pela legislação Brasileira. Demostrando a baixa qualidade sanitária do mel comercializado nessa região do estado do Pará.

Lactobacillus pentosus ABHEAU-05: An in vitro digestión resistant lactic acid bacterium isolated from a traditional fermented Mexican beverage / Lactobacillus pentosus ABHEAU-05: una bacteria ácido láctica resistente a la digestión in vitro aislada de una bebida fermentada tradicional mexicana

Abstract The health benefits attributed to probiotics generate interest in the search of competent strains adapted to several ecological niches, especially those related to traditional beverages and foods of each country. Pineapple tepache, a traditional Mexican fermented beverage, was used for the isolation of lactic acid bacteria with probiotic potential, one of which withstood the in vitro tests. The isolated strain AB-05, which exhibited the tested probiotic functional properties, was designated as Lactobacillus pentosus ABHEAU-05. The sequence was registered in GenBank under access code MK587617. This study is the first report of a lactic acid bacterium with in vitro digestion resistance isolated from pineapple tepache. The survival of L. pentosus ABHEAU-05 in a symbiotic medium was proven using fermented milk enriched with inulin. The in vitro digestion-resistant probiotic activity of lactobacilli was measured through analysis of pH and proteolysis. Results showed that L. pentosus grew properly in fermented milk; therefore, this microorganism could be used in the manufacture of this kind of products. The concentration of L. pentosus reached up to 8.5 logCFU/ml after 40 h of fermentation. In addition, the production of peptides and the decrease in pH indicated the vigorous and active metabolic state of the lactic acid bacterium tested. The activity and the concentration of this microorganism were maintained during refrigeration. The results of this research conclude that L. plantarum ABHEAU-05 is an in vitro digestion-resistant microorganism that can be used as a starter culture for the production of functional foods of dairy origin.

Resumen Los beneficios a la salud atribuidos a los probióticos generan interés en la búsqueda de cepas competentes adaptadas a varios nichos ecológicos, especialmente los relacionados con bebidas y alimentos tradicionales de cada país. En este estudio, se aisló del tepache de pina, una bebida fermentada tradicional mexicana, una bacteria láctica resistente a la digestión in vitro. Entre 5 bacterias aisladas, una de ellas soportó las pruebas simuladas de digestión gastrointestinal. Se analizó la resistencia a sales biliares, a condiciones ácidas y al ataque enz-imático con pepsina. La bacteria aislada, que exhibió las propiedades funcionales probióticas referidas, fue identificada como Lactobacillus pentosus y designada como L. pentosus ABHEAU-05. La secuencia fue depositada en GenBank (acceso MK587617). Se comprobó la supervivencia de L. pentosus ABHEAU-05 en una leche fermentada adicionada con inulina y su resistencia a la digestión in vitro mediante el análisis del pH y la proteólisis. Los resultados muestran que la leche fermentada es una matriz adecuada, donde L. pentosus ABHEAU-05 se desarrolla sin inconvenientes, alcanzando un título de 8,5 logufc/ml después de 40 h de fermentación. Además, la producción de péptidos y el descenso del pH indicaron el estado metabólico vigoroso y activo del microorganismo probiótico. Se concluye que L. pentosus ABHEAU-05 es un microorganismo resistente a la digestión in vitro, que puede servir como cultivo iniciador para la producción de alimentos de origen lácteo. Este es el primer informe acerca del aislamiento de una bacteria ácido láctica resistente a la digestión in vitro a partir del tepache de piña.

Prevalence of Campylobacter jejuni and Campylobacter coli from broilers at conventional and kosher abattoirs and retail stores / Prevalencia de Campylobacter jejuni y Campylobacter coli en carcasas de pollo procedentes de frigoríficos, faena tradicional y kosher, y de locales de expendio

Abstract We studied and compared the prevalence of Campylobacter jejuni and Campylobacter coli in chicken carcasses from conventional and kosher broiler abattoirs and retail stores. The prevalence of thermotolerant Campylobacter-positive carcasses was 94.0 (kosher) and 32.0% (conventional) (p< 0.0001), while the prevalence of samples contaminated with C. jejuni, C. coli and simultaneously with both species was 36.0, 2.0 and 56.0% (kosher) and 26.0, 4.0 and 2.0% (conventional) (p< 0.0001), respectively. Samples of chicken carcasses (n = 25) and food contact surfaces (tables, n = 25; knives, n=25) from 25 retails were collected and risk quantification was performed. Retails were categorized as high-risk (n = 11), moderate-risk (n = 11) and low-risk (n = 3). Nineteen (76.0%) carcasses, 20 (80.0%) tables and 18 (72.0%) knives were Campylobacter-positive. Retails and abattoirs proved to be sources of carcass contaminaron with Campylobacter spp. Carcasses from kosher abattoirs were mostly contaminated with Campylobacter spp., whereas C. coli was the most prevalent species isolated from carcasses in retail stores.

Resumen El objetivo del estudio fue determinar y comparar la prevalencia de Campylobacter jejuni y Campylobacter coli en carcasas de pollo obtenidas en frigoríficos por faena convencional y kosher, y en locales de expendio. La prevalencia de Campylobacter spp. termotolerante fue del 94,0 (kosher) y del 32,0% (convencional) (p< 0,0001). La prevalencia de muestras contaminadas con C. jejuni, C. coli y con ambas especies fue del 36,0, del 2,0 y del 56,0% (Kosher) y del 26,0, del 4,0 y del 2,0% (convencional) (p< 0,0001), respectivamente. Se tomaron muestras de carcasas (n = 25) y superficies (tablas, n = 25; cuchilla, n = 25) en 25 locales. Los locales fueron categorizados como de riesgo alto (n = 11), moderado (n = 11) y bajo (n = 3). Diecinueve (76,0%) carcasas, 20 (80,0%) tablas y 18 (72,0%) cuchillas fueron positivas para Campylobacter spp. Frigoríficos y locales fueron fuente de contaminación de carcasas con Campylobacter spp. La prevalencia de Campylobacter spp. fue mayor en carcasas kosher. Campylobacter coli fue la especie más prevalente en carcasas de locales.

Detecção de listeria monocytogenes em produtos lácteos e produtos cárneos à base de frango / Detection of listeria monocytogenes in dairy products and chicken meat / Detección de listeria monocytogenes en productos lácteos y en productos cárnicos a base de pollo

Listeria monocytogenes é um patógeno de origem alimentar que frequentemente causa infecções, podendo até ser fatal. Trata-se de um microrganismo ubiquitário, transmitido ao ser humano principalmente por meio dos alimentos, como os produtos prontos para o consumo. O objetivo deste estudo foi verificar os índices de positividade para L. monocytogenes em queijos e produtos cárneos à base de frango, analisados em um laboratório de microbiologia de alimentos do Rio Grande do Sul. A triagem inicial das amostras seguiu o protocolo AOAC, método n° 2004.02, 2004. A confirmação dos resultados positivos foi realizada conforme Instrução Normativa nº 62/2003 (Mapa) e ISO 11290-1:1996, Amd.1:2004. Foram analisadas 666 amostras de queijos de baixa umidade, 3.897 de média umidade e 826 de alta umidade. Dos produtos à base de frango foram analisadas 547 amostras de salsicha, 172 de mortadela e 24 de linguiça. O estudo verificou que os queijos de baixa umidade estão significativamente associados ao resultado positivo (p=0,002) para L. monocytogenes e os queijos de alta umidade associaram-se ao resultado negativo (p=0,002). Com relação aos produtos à base de frango, a salsicha esteve significativamente associada ao resultado negativo para L. monocytogenes (p≤0,01), e a mortadela significativamente associada ao resultado positivo (p≤0,01). Visto que de modo geral esses produtos são consumidos diretamente, sem o emprego de calor, sugere-se reforçar tanto o controle sobre as boas práticas de fabricação quanto o monitoramento dos produtos.

Listeria monocytogenes is a foodborne pathogen that often causes infections and may even be fatal. It is an ubiquitous microorganism, transmitted to humans mainly through food such as ready-to-eat products. This study sought to verify the positivity indexes for L. monocytogenes in cheese and chicken meat products, analyzed in a food microbiology laboratory in Rio Grande do Sul, Brazil. The initial sample screening followed the AOAC protocol, Method No. 2004.02, 2004. Confirmation of positive results was performed according to Normative Instruction 62/2003 (MAPA) and ISO 11290-1: 1996, Amd.1: 2004. A total of 666 low moisture, 3897 medium moisture and 826 high moisture cheese samples were analyzed. Of the chicken meat products, 547 wiener, 172 mortadella and 24 sausage samples were analyzed. Results showed that low moisture cheeses were significantly associated with a positive result (p=0.002) for L. monocytogenes, while high moisture cheeses were associated with a negative result (p= 0.002). As for chicken meat products, the wiener was significantly associated with the negative result for L. monocytogenes (p≤0.01) and the mortadella significantly associated with the positive result (p≤0.01). Since most of these products are consumed directly, without the use of heat, it is suggested to reinforce both the control over Good Manufacturing Practices and the monitoring of the products.

Listeria monocytogenes es un patógeno de origen alimentario causante muchas veces de infecciones, incluso fatales. Es un microorganismo ubiquitario, que se transmite al hombre principalmente a través de los alimentos, generalmente por productos listos para el consumo. El objetivo de este estudio fue verificar los índices de positividad para L. monocytogenes en quesos y productos cárnicos a base de pollo, analizados en un laboratorio de microbiología de alimentos de Rio Grande do Sul (Brasil). El tamizaje inicial de las muestras siguió el protocolo AOAC, método 2004.02, 2004. La confirmación de los resultados positivos fue realizada conforme a la Instrucción Normativa 62/2003 (Mapa) e ISO 11290-1:1996, Amd.1:2004. Se analizaron 666 muestras de quesos de baja humedad, 3.897 de media humedad y 826 de alta humedad. De los productos a base de pollo se analizaron 547 muestras de salchichas, 172 de mortadela y 24 de chorizos. Este estudio verificó que los quesos de baja humedad fueron significativamente asociados al resultado positivo (p=0,002) para L. monocytogenes, y los quesos de alta humedad al resultado negativo (p=0,002). En cuanto a los productos a base de pollo, las salchichas estuvieron significativamente asociadas al resultado negativo para L. monocytogenes (p≤0,01), y la mortadela fue significativamente asociada al resultado positivo (p≤0,01). Dado que la mayoría de estos productos son consumidos directamente, sin cocción, se sugiere un mayor control de las buenas prácticas de fabricación y de monitoreo de los mismos.

First molecular detection of Coxiella burnetii in Brazilian artisanal cheese: a neglected food safety hazard in ready-to-eat raw-milk product

ABSTRACT Background: Global publications on Q fever have increased after the 2007 epidemic in the Netherlands. However, the epidemiology of Q fever/coxiellosis in Brazil is still poorly understood. Accordingly, there have been few studies investigating the presence of Coxiella burnetii in dairy products around the world, especially in Brazil, where consumption of fresh cheese made from raw-milk is very high. Objective: This study was a random survey to assess the prevalence of C. burnetii by PCR in traditional Minas artisanal cheese from the Serro microregion, Brazil, which is manufactured from bovine raw-milk. Methods: DNA extracted from 53 cheese samples were analyzed by nested PCR with C. burnetii-specific primers and the products confirmed by DNA sequencing. Results: Out of the 53 cheese samples five (9.43%) were C. burnetii DNA-positive, each coming from one of the respective randomly selected manufacturing agroindustries.Based on our results, it is estimated that 1.62 tons/day of ready-to-eat cheese made from raw-milk from a total of 16.2 tons produced daily in the study region are contaminated with C. burnetii. Conclusion: To our knowledge, this is the first report of highly heat-resistant zoonotic pathogen in raw-milk Brazilian artisanal cheese. This food safety hazard has been completely neglected in ready-to-eat raw-milk Brazilian artisanal cheese and could imply potential threats to consumers, since C. burnetii survives in artisanal cheese submitted to long ripening periods. Thus, this work established random and representative baseline prevalence of C. burnetii in this food product in Brazil. Further epidemiological studies, monitoring trends and setting control targets are warranted. Finally, these results point out the importance of including C. burnetii in animal and public health surveillance programs.

Preparing multicomponent snack bars based on tapioca flour, Brazil nut, and regional fruits / Preparación de barras multicomponentes a base de harina de tapioca, castaña de brasil y frutos regionales

ABSTRACT This study aimed to develop and assess the physicochemical, sensory parameters, and shelf life estimation of multicomponent snack bars based on tapioca flour, Brazil nut, and açaí or cupuassu pulp. The physicochemical composition of açaí- and cupuassu-flavored snack bars had, respectively, 0.92 and 0.99% ash, 19.22 and 17.02% lipids, 3.02 and 3.03% protein, 1.06 and 1.69% fiber, and 448 and 436 kcal/100 g energy value. The shear stress test showed the consumer needs to bite more strongly to break the açaí-flavored bar. The opposite was observed in the hardness test, in which the bite compression force during mastication was greater for the cupuassu-flavored bar. The bars had water activity below 0.6, which denotes microbiological stability. The sensory analysis ranked the bars between "liked slightly" and "liked very much," which was confirmed by the acceptability index above 75% for all attributes assessed. According to the results a significant increase in water activity over storage was observed suggest the packaging used in the tests did not present a satisfactory barrier to water vapor permeability. Only water activity was used to estimate shelf life, which was determined as 58 days and 49 days for the açaí- and cupuassu-flavored bars, respectively. Thus, the snack bars represent an alternative for athletes as well as individuals with celiac disease since they are gluten free.

RESUMEN El objetivo de este trabajo fue desarrollar y evaluar los parámetros físicos, físico-químicos, microbiológicos, sensoriales y la vida útil en estante de barras a base de harina de tapioca, castaña de Brasil y pulpa de açaí o cupuaçu. En cuanto a la composición físico-química, las barras multicomponentes sabor açaí y cupuaçu presentaron, respectivamente, 0,92 y 0,99% de cenizas, 19,22 y 17,02% de lípidos, 3,02 y 3,03% proteínas, 1,06 y 1,69% de fibras y 448 y 436 kcal/100g de valor energético. La prueba de cizallamiento y dureza mostraron que el consumidor necesita una fuerza de mordida mayor para romper la barra sabor açaí. El comportamiento contrario fue observado en la prueba de dureza donde la fuerza de compresión de la mordida, durante la masticación, fue mayor en la barra sabor cupuaçu. Para el análisis sensorial se observó que las barras evaluadas recibieron notas situadas entre las categorías "me gustó ligeramente" y "me gustó mucho", resultado comprobado por el índice de aceptabilidad con valores superiores al 75% para todos los atributos evaluados. De acuerdo con los resultados, se observó un aumento significativo en la actividad de agua durante el almacenamiento, lo que sugiere que el embalaje utilizado en las pruebas no presentó una barrera satisfactoria para la permeabilidad al vapor de agua. Para la estimación de vida de estante sólo la actividad de agua fue utilizada para los cálculos, siendo el tiempo de vida de estante determinado en 58 días para la barra sabor açaí y 49 días para la barra sabor cupuaçu. Así, las barras multicomponentes elaboradas representam una alternativa para atletas, así como para portadores de la enfermedad celíaca, visto la ausencia de gluten en su composición.

Correlação estatística entre parâmetros microscópicos e microbiológicos em pimenta-do-reino moída (Piper nigrum L) comercializada em Minas Gerais / Statistical correlation between microscopic and microbiological parameters in ground black pepper ( Pipper nigrum L) sold in Minas Gerais

A ausência de Boas Práticas de Fabricação durante a colheita, processamento e manuseio da pimenta-do-reino pode acarretar a contaminação do produto com sujidades microscópicas e microrganismos. Foram analisadas 227 amostras de pimenta-do-reino, comercializadas em Minas Gerais, coletadas entre 2008 e 2018, quanto à presença de fragmentos de pelo de roedor e de insetos, coliformes a 45°C ou Escherichia coli e Salmonella spp. Para verificar se havia correlação entre os contaminantes, foi empregado método estatístico de regressão linear múltipla. As análises microscópicas evidenciaram presença de fragmentos de pelo de roedor e de insetos em 26,0% e 30,5% das amostras, respectivamente, em valores superiores ao limite tolerado pela RDC 14/2014. Quanto às análises microbiológicas, 10% das amostras apresentaram coliformes a 45°C ou E. coli acima dos limites tolerados pela RDC 12/2001 e em 8,8% das amostras foi detectada presença de Salmonella spp. A avaliação estatística mostrou que houve correlação entre presença de fragmentos de insetos e de pelos de roedor e a contaminação por Salmonella spp. em pimenta-do-reino. Os resultados demonstraram a importância das análises microscópica e microbiológica simultaneamente para detecção dos contaminantes presentes bem como das possíveis relações existentes entre eles e a melhor compreensão dos fatores que favorecem as contaminações. (AU)

The absence of Good Manufacturing Practices during harvesting, processing and handling of black pepper can lead to contamination of the product with microscopic dirt and microrganisms. Two hundred and twenty seven black pepper samples, commercialized in Minas Gerais, collected between 2008 and 2018, were analyzed for the presence of rodent and insect fragments, coliforms at 45°C or Escherichia coli and Salmonella spp. To verify whether there was a correlation between the contaminants, a statistical method of multiple linear regression was used. Microscopic analysis showed the presence of rodent and insect fragments in 26.0% and 30.5% of the samples, respectively, in values above the limit tolerated by RDC14/2014. As for the microbiological analysis, 10% of the samples presented coliforms at 45°C or E.coli above the limits tolerated by the RDC 12/2001 and in 8.8% of the samples Salmonella spp. were detected. The statistical evaluation showed that there was a relationship between the presence of insect fragments and rodent hair and contamination by Salmonella spp. in black pepper. The results demonstrated the importance of simultaneous microscopic and microbiological analysis to detect the contaminants present, as well as the possible relationships between them and better understanding of the factors that favor contamination. (AU)

Resistencia a nitrofuranos en Salmonella enterica aisladas de carne para consumo humano / Nitrofuran resistance in Salmonella enterica isolated from meat for human consumption

RESUMEN En el presente estudio, se analizaron los mecanismos de resistencia a nitrofuranos en 18 muestras cár nicas con Salmonella enterica (15 de pollo, 2 de ternera y 1 de cerdo) de mercados de Lima (Perú). Determinaron los serotipos de los aislamientos y la sensibilidad a furazolidona y nitrofurantoina (con y sin el inhibidor de bombas de expulsión Phenyl-Arginine-β-Naphthylamide [PAβN]), las mutaciones en los genes snrA y cnr por PCR y la transferabilidad de la resistencia por conjugación. Se identificaron 15 muestras con S. infantis (13 muestras de pollo), 2 con S. enteritidis y 1 con S. anatum. Todos los aisla mientos, excepto S. anatum, fueron resistentes a ambos nitrofuranos (concentración mínima inhibidora [CMI] a furazolidona: 32-64 µg/mL, CMI a nitrofurantoina: 128-256 µg/mL), sin diferencias al adicio narse PAβN. Todos los aislamientos resistentes a nitrofuranos presentaron sustituciones en snrA y cnr (S. infantis: snrA STOP-151; cnr STOP-137; S. enteritidis: snrA STOP-180; cnr STOP-179). No se detectaron mecanismos transferibles de resistencia a nitrofuranos.

ABSTRACT The mechanisms of resistance to nitrofurans from 18 meat samples with Salmonella enterica (chicken: 15; beef: 2; pork: 1) collected in Lima (Peru) were analyzed. The isolates were serotyped and the susceptibility levels to furazolidone and nitrofurantoin [with and without the efflux pump inhibitor Phenyl-Arginine- β-naphthylamide (PAβN)], the presence of mutations in the snrA and cnr genes and the transferability of resistance by conjugation were established. Fifteen samples with S. infantis (13 from chicken samples), 2 with S. enteritidis and 1 with S. anatum were identified. All isolates except the S. anatum were resistant to both nitrofurans showing MICs (minimum inhibitory concentration) of furazolidone and nitrofurantoin of 32-64 μg/mL and 128-256 μg/mL, respectively. The addition of PAßN had no effect on the MIC levels. All nitrofuran-resistant isolates showed amino acid codon alterations at both snrA and cnr (S. infantis: snrA STOP-151; cnr STOP-137; S. enteritidis: snrA STOP-180; cnr STOP-179). No transferable mecha nisms of nitrofuran resistance were detected.

Differences of the structure, succession and function of Clostridial communities between jiupei and pit mud during Luzhou-flavour baijiu fermentation / 生物工程学报

Clostridia inhabiting in jiupei and pit mud plays key roles in the formation of flavour during the fermentation process of Luzhou-flavour baijiu. However, the differences of Clostridial communities between jiupei and pit mud remains unclear. Here, the species assembly, succession, and metabolic capacity of Clostridial communities between jiupei and pit mud were analysed by high-throughput sequencing and pure culture approaches. The ratio of Clostridial biomass to bacterial biomass in the pit mud was relatively stable (71.5%-91.2%) throughout the fermentation process. However, it varied widely in jiupei (0.9%-36.5%). The dominant Clostridial bacteria in jiupei were Clostridium (19.9%), Sedimentibacter (8.8%), and Hydrogenispora (7.2%), while Hydrogenispora (57.2%), Sedimentibacter (5.4%), and Caproiciproducens (4.9%) dominated in the Clostridial communities in pit mud. The structures of Clostridial community in pit mud and jiupei were significantly different (P=0.001) throughout fermentation. Isolated Clostridial strains showed different metabolic capacities of volatile fatty acids in pure culture. Spatial and temporal heterogeneity of Clostridial communities existed in the baijiu fermentation pit, which was closely related to the main flavour components of Luzhou-flavour baijiu.

Strain variability of foodborne pathogens in microbiological risk assessment - a review / 生物工程学报

Strain variability is one of the most important factors to influence the accuracy of foodborne pathogens risk assessment, such as Listeria monocytogenes, Salmonella spp. Strain-to-strain variation is defined as the inherent differences among identically treated strains of the same microbial species. The differences cannot be eliminated by changing test methods or improving test protocols. This review addresses presently related studies of strain variability. Based on the effect of strain variability on the outcome of risk assessment, we summarize sources of variabilities in food chain, strain phenotypic variabilities and the methods to integrate strain variability in growth and inactivation into predictive modelling, and indicate the inadequacies in the study of strain variability. We suggest further study the mechanism of strain variability, expand the comparison of variability among different sources, and integrate the variability of gene expression, protein and cell metabolism into the predictive modelling.

Genetic Diversity, Antimicrobial Resistance, and Virulence Genes of Isolates from Clinical Patients, Tap Water Systems, and Food / 生物医学与环境科学（英文）

Objective@#This study aimed to evaluate the genetic diversity, virulence, and antimicrobial resistance of isolates from clinical patients, tap water systems, and food.@*Methods@#Ninety isolates were obtained from Ma'anshan, Anhui province, China, and subjected to multi-locus sequence typing (MLST) with six housekeeping genes. Their taxonomy was investigated using concatenated sequences, while their resistance to 12 antibiotics was evaluated. Ten putative virulence factors and several resistance genes were identified by PCR and sequencing.@*Results@#The 90 isolates were divided into 84 sequence types, 80 of which were novel, indicating high genetic diversity. The isolates were classified into eight different species. PCR assays identified virulence genes in the isolates, with the enterotoxin and hemolysin genes , , , and found in 47 (52.2%), 13 (14.4%), 22 (24.4%), and 12 (13.3%) of the isolates, respectively. The majority of the isolates (≥ 90%) were susceptible to aztreonam, imipenem, cefepime, chloramphenicol, gentamicin, tetracycline, and ciprofloxacin. However, several resistance genes were detected in the isolates, as well as a new variant.@*Conclusions@#Sequence type, virulence properties, and antibiotic resistance vary in isolates from clinical patients, tap water systems, and food.