Abstract The implementation of effective cleaning and disinfection procedures is crucial to ensure quality control and food safety in food services. This study aimed to evaluate the hygienic conditions in the gastronomy laboratories of a university in Colombia. The study conducted ATP bioluminescence detection and microbiological analysis on various surfaces and food handler's hands. The results indicated the presence of aerobic mesophilic bacteria and total coliforms on the surfaces, but no Escherichia coli, Staphylococcus aureus, Listeria monocytogenes, or Salmonella spp. The cutting-board had the highest microbial counts, while the countertop and serving dish had the lowest. Total coliform counts exceeded the acceptable limits on most surfaces. Correlations between ATP levels and microbial counts were not significant. ATP measurements indicated organic contamination, but not necessarily high microbial loads. The findings emphasize the importance of proper cleaning, disinfection protocols, and personal hygiene practices to prevent cross-contamination and ensure food safety. services Colombia handlers handler s hands coli aureus monocytogenes spp cuttingboard cutting board lowest significant contamination loads protocols crosscontamination cross

Abstract The serrano artisanal cheese (SAC) is a traditional raw milk dairy produced in southern Brazil. The maturation temperature plays a crucial role regarding the cheeses’ microbiological and physicochemical features and has been underexplored when it comes to unpasteurized milk dairy in Brazil. The objective of the present work is to evaluate the effect of ripening temperature on foodborne bacteria (total and thermotolerant coliforms, positive coagulase Staphylococcus and the production of its enterotoxin, Listeria monocytogenes, Escherichia coli and Salmonella spp.) and physicochemical attributes (moisture, water activity, pH, acidity and sodium chloride concentration) of SAC during maturation at 5ºC-20ºC for up to 60 days. Metagenomic analysis was also evaluated through the rDNA 16S method at ripening time of 0-60 days. The samples were safe for L.monocytogenes, E.coli, Salmonella spp. and staphylococcal toxin. The physicochemical parameters reached legal boundaries as follows: moisture, after 30 days at 5ºC; fat, after 30 days at 12.5ºC and 20ºC; fat at dry extract, after 30 days at 12.5ºC or 15 days at 5ºC. The microbiological features indicate that positive coagulase Staphylococcus reached legal conditions after 30 days when cheeses were ripped at 12.5ºC and 20ºC; thermotolerant coliforms after 30 days at 12.5ºC and 20ºC; and total coliforms after 15 days at 20ºC. Lower temperatures lead to lower inactivation rates, and Staphylococcus did not reach legal parameters at 5ºC positive coagulase regarding moisture, water activity and pH reduction. Meanwhile, sodium chloride concentration and enhanced acidity played important role regarding foodborne pathogen inactivation. The main lactic acid bacteria within the cheeses during ripening were Enterococcus sp. and Lactococcus sp. (SAC Brazil enterotoxin monocytogenes spp moisture (moisture 5ºC20ºC ºCºC 20ºC ºC 6 S 060 0 0-6 Lmonocytogenes L L.monocytogenes Ecoli E E.coli toxin follows 3 125ºC 12 extract 1 rates reduction Meanwhile sp 06 0-

Abstract Paipa cheese is the unique Colombian ripened cheese produced from raw milk that has a protected designation of origin (PDO); nonetheless, to date, the dairy product lacks a defined sensory profile, since no study has been previously performed. The aim of this study was to approach the definition of the sensory attributes of the Paipa cheeses that are produced within the PDO region in order to establish the organoleptic aspects of the PDO regulation. A trained panel of five members used the multidimensional approach as a descriptive sensory analysis to establish the sensory profile of Paipa cheese; such analysis was complemented with the method used for PDO cheeses were three cheese producers, two government delegates, one gastronomy expert and two Paipa cheese researchers participated in the descriptive sensory analysis. A microbiological assessment (mesophilic aerobic bacteria, lactic acid bacteria, total and fecal coliforms, coagulase-positive Staphylococci, Salmonella spp. and Listeria monocytogenes) of cheese samples was carried out prior to sensory analysis to guarantee the safety of the samples. The descriptive sensory analysis was performed with 17 cheese samples that represented 77% of Paipa cheese produced in the PDO region. 82 sensory descriptors were identified and 47 were finally established (seven descriptors for appearance, 15 for odor, 15 for taste and 10 for texture) for describing the sensory profile of Paipa cheese. Due to the presence of pathogenic bacteria, the texture and taste profiles of Paipa cheese were based only on three samples. Sensory profiles of cheese samples were highly heterogeneous and it may be a consequence of the variations among raw milk used and/or manufacturing practices of cheese producers. Therefore, in order to find the sensory identity of Paipa cheese and guarantee quality and safety, cheese production and raw milk characteristics must be defined and regulated among milk and Paipa cheese producers. (PDO) nonetheless date regulation producers delegates mesophilic bacteria coliforms coagulasepositive coagulase positive Staphylococci spp monocytogenes 1 77 8 4 seven appearance odor andor or Therefore (PDO 7

Resumo O queijo Paipa é o único queijo curado colombiano com denominação de origem protegida (DOP) e é feito com leite cru; No entanto, até o momento, o produto não apresenta um perfil sensorial definido, já que nenhum estudo foi feito até o momento. O objetivo deste estudo foi abordar a definição dos atributos sensoriais dos queijos Paipa produzidos na região do DOP, a fim de estabelecer os aspectos organolépticos da regulação DOP. Um painel treinado de cinco membros utilizou o teste de análise sensorial descritiva por abordagem multidimensional para estabelecer o perfil sensorial do queijo Paipa; esta análise foi complementada com o método utilizado para queijos DOP, no qual participaram também três produtores de queijo, dois delegados do governo, um especialista em gastronomia e dois pesquisadores do queijo Paipa. A avaliação microbiológica (bactérias aeróbicas mesofílicas, bactérias do ácido láctico, coliformes totais e fecais, estafilococos coagulase positiva, Salmonella spp. Listeria monocytogenes) das amostras de queijo foi feita antes da análise sensorial a fim de garantir a segurança das amostras a serem testadas. A análise sensorial descritiva foi feita com 17 amostras de queijos que representaram 77% dos queijos Paipa produzidos na região DOP. 82 descritores sensoriais foram identificados e finalmente 47 foram estabelecidos (sete descritores para aparência, 15 para odor, 15 para sabor e 10 para textura) para descrever o perfil sensorial do queijo Paipa. Devido à presença de bactérias patogênicas, os perfis de textura e sabor do queijo Paipa estiveram baseados em apenas três amostras. Os perfis sensoriais das amostras de queijo foram altamente heterogêneos e isso pode ser uma consequência da grande variação nas características do leite cru e/ou nas práticas de elaboração dos produtores de queijo. Portanto, para encontrar a identidade sensorial do queijo Paipa e garantir sua qualidade e segurança sanitária, a produção de queijo e as características do leite cru devem ser definidas e regulamentadas entre os produtores de leite e queijo Paipa. DOP (DOP entanto momento definido governo mesofílicas láctico fecais positiva spp monocytogenes testadas 1 77 8 4 sete aparência odor patogênicas eou ou Portanto sanitária 7

RESUMEN En este estudio se investigó la actividad antimicrobiana de cepas de Enterococcus aisladas del contenido intestinal del caracol de jardín (Helix aspersa Müller) mediante el ensayo de difusión en agar. Entre los 90 aislamientos obtenidos, 37 exhibieron actividad inhibitoria contra una o más cepas de Listeria ensayadas. Sobre la base de la mayor actividad, se seleccionaron 16 cepas de enterococos para posteriores estudios. Ninguna de las cepas exhibió β-hemólisis o actividad de gelatinasa y todas resultaron sensibles a la vancomicina. El tratamiento con lisozima y catalasa no afectó la actividad anti-Listeria; por otra parte, la actividad enzimática de la tripsina abolió la actividad inhibitoria de los sobrenadantes libres de células (SLC), confirmando la naturaleza proteica de los compuestos activos. En todos los casos, la actividad de los SLC permaneció estable después del tratamiento térmico (100 ºC, 10 min). Estas características están de acuerdo con bacteriocinas de tipo II producidas por bacterias ácido-lácticas. Entre los 16 aislados seleccionados se lograron identificar mediante pruebas bioquímicas a nueve cepas como E. avium, cinco como E. mundtii y dos como E. faecium. La mayor actividad se presentó en cepas de E. mundtii con valores entre 163 840 y 327 680 unidades arbitrarias/ml (UA/ml). Los resultados sugirieren que los caracoles de jardín podrían ser una fuente adecuada para el aislamiento de cepas de Enterococcus bacteriogénicos con potenciales aplicaciones tecnológicas, bioconservación de alimentos o como probióticos.

ABSTRACT In this study, the antimicrobial activity of Enterococcus strains isolated from the gut content of garden snail (Helix aspersa Müller) was investigated by agar diffusion assay. Among the 90 isolates obtained, 37 exhibited inhibitory activity against one or more of the Listeria strains tested. Based on the highest activity, 16 enterococci strains were selected for further studies. None of these strains exhibited beta-hemolysis or gelatinase activity and all were sensitive to vancomycin. Treatment with lysozyme and catalase did not affect the anti-Listeria activity. Moreover, the enzymatic activity of trypsin abolished the inhibitory action of the cell-free supernatants (CFS), confirming the protein nature of the active compounds. In all cases CFS activity remained stable after heat treatment (100 ºC, 10 min). These characteristics described agree with bacteriocin type II of lactic acid bacteria. Among the 16 selected isolates, biochemical test allowed the identification of nine E. avium strains, five of E. mundtii and two of E. faecium. The highest activity was observed in E. mundtii strains with values between 163 840 to 327 680 arbitrary units/ml (UA/ml). These results suggested that garden snails could be a suitable source for the isolation of bacteriocinogenic Enterococcus strains with potential technological applications, food biopreservation or probiotics.

Introduction: Acute bacterial meningitis (ABM) is denifed as the inflammation of leptomeninges due to the presence of pyogenic bacteriae. Epidemiology is variable and multifactorial. In spite of advance in medicine, ABM’s mortality has remained stable, hence the need to study the causative microorganisms in order to guide prevention and treatment strategies. Objectives: To determine the prevalence of the etiological agents of ABM confirmed in adults in a medium complexity hospital located in Quillota, Chile, between 2012 and 2018, to establish the rate of resistance of these to antibiotics. Determine the profile of the patients and establish the relationship between profile, etiological agent identified and outcome. Methods: A sample of 38 cases with ABM was evaluated during, the prevalence of the pathogens involved was established and a statistical analysis was carried out considering the risk factors of patients, their days of in-hospital stay and their condition at hospital discharge. Results: We analyzed 38 cases, 15 without isolated pathogens, 13 of Streptococcus pneumoniae, 4 of Haemophilus spp., 3 of Neisseria meningitidis, 2 of Staphylococcus spp. and we obtained one case of Mycobacterium tuberculosis. In the group without isolated pathogens, a better prognosis was observed, lower blood CRP values and higher glucose on spinal fluid values. 6 deaths per ABM were recorded. Conclusion: The prevalence of etiological agents was similar to that described in the literature, with pneumococcus as the most frequent microorganism, no cases of Listeria monocytogenes were reported. Probably in the group in which no agent was isolated, cases of viral meningitis were included.

Resumen Introducción: La Meningitis Bacteriana Aguda (MBA) corresponde a la inflamación de las leptomeninges por presencia de bacterias piógenas. La epidemiología es variable y depende multifactorial. A pesar de los avances en medicina la mortalidad de la MBA se ha mantenido estable, evidenciando la necesidad de estudiar esta patología para orientar estrategias de prevención y tratamiento. Objetivos: Determinar la prevalencia de los agentes etiológicos de MBA confirmadas en adultos en el Hospital San Martín de Quillota (HSMQ) entre los años 2012 y 2018. Establecer la tasa de resistencia a antibióticos. Determinar el perfil de los pacientes, y establecer la relación entre perfil, agente etiológico identificado y desenlace. Métodos: c muestra de 38 casos, se estableció la prevalencia de los patógenos involucrados y se realizó un análisis estadístico considerando los factores de riesgo, sus días de estadía y su condición al egreso hospitalario. Resultados: 15 casos en que no se aisló patógeno en LCR (líquido cefalorraquídeo), 13 MBA por neumococo, 4 por Haemophilus spp, 3 por meningococo, 2 por Staphylococcus spp y 1 por Mycobacterium tuberculosis. En el grupo sin agente aislado se observó un mejor pronóstico, valores de PCR (proteína C reactiva) en sangre menores y valores de glucorraquia mayores. Se registraron 6 fallecimientos por MBA. Conclusión: La prevalencia de los agentes etiológicos fue similar a la descrita en la literatura, con neumococo como el microorganismo más frecuente, no se reportaron casos de Listeria monocytogenes. Probablemente en el grupo sin agente aislado se incluyeron casos de meningitis virales.

RESUMEN El objetivo general del presente estudio fue determinar la presencia de Salmonella spp, Escherichia coli O157, Staphylococcus aureus y Listeria monocytogenes en alimentos preparados listos para el consumo como pollo, arroz y ensaladas en restaurantes escolares de 7 departamentos de Colombia. El estudio fue descriptivo y transversal. Se realizaron encuestas en donde se preguntaron temas relacionados con condiciones higiénico-sanitarias y listas de chequeo en el cual se evaluaron temas de infraestructura y uso de elementos protección personal durante la manipulación de alimentos. La selección de la muestra se llevó a cabo por medio de un diseño probabilístico bietápico, con un nivel de confianza del 95%, para la recolección de información se utilizó el programa de captura CSPro y para estimar asociaciones se usó paquetes estadístico Stata 12. Resultados: Se visitaron 7 departamentos, 72 municipios, 332 restaurantes y se recolectaron 497 muestras. El 61% de las muestras correspondió a arroz, ensalada 23% y pollo 16%. El microorganismo más frecuentemente encontrado fue Listeria monocytogenes 1,6%, Salmonella spp 0,6% y Staphylococcus aureus 0,4%. No hubo presencia de E. coli O157H7. Conclusiones: Se detectó la presencia de microorganismos patógenos en los restaurantes escolares.

Introduction: Fresh cheese is consumed because of its healthy, nutritional, and safety characteristics. These features become less relevant when appropriatepreparation and storage conditions are not met. Objective: The objective was to evaluate the microbiological safety of commercial and artisanal fresh cheeses sold in the city of Chillán. Methods: A total of 80 fresh cheese samples were analyzed: 40 commercial (brands 1 and2) and 40 artisanal (brands 3 and 4). Enterobacteriaceae (ENT) and Escherichia coli were quantified by NCh 2676 and 2636 (2002). Salmonella, Staphylococcus aureus, and Listeria monocytogenes used NCh 2675, 2671 (2002), ISO 11290-1 (1996 rev 2004), and were confirmed by PCR. Cronobacter spp was identified by multilocus sequence typing (MLST) using criteria from http://www.pubmlst.org/cronobacter. Furthermore, staff and sale hygiene requirements were identified with Sanitary Food Regulations (SFR) checklists. Results: Overall ENT medians were 30 000 000 UFC/g (2 000 000 - 300 000 000) and E. coli were 450 UFC/g NMP/g (33 - 1 100); there were no significant differences in counts for both brand and sale location indicators (p>0.05). Compliance with SFR hygiene requirements was 50%. Positivity of L. monocytogenes was 8.8%; Salmonella spp and S. aureus were not detected. Suspected Cronobacter spp strains were isolated and identified as Franconibacter helveticus. Conclusions: The evaluated fresh cheeses did not meet SFR microbiological criteria and were therefore not safe to eat. The presence of L. monocytogenes is clearly a health risk in hypersensitive population groups that consume this food.

Introducción: El quesillo es un alimento muy consumido en la población por sus características nutritivas y de inocuidad. Sin embargo, estas cualidades pierden relevancia si no se respetan condiciones adecuadas en su elaboración y almacenamiento. Objetivo: Evaluar la inocuidad microbio-lógica de quesillos comerciales y artesanales expendidos en Chillán. Metodología: Se analizaron 80 muestras de quesillo: 40 comerciales (marca 1 y 2) y 40 artesanales (marca 3 y 4). Se cuantificó Enterobacteriaceae (ENT) y Escherichia coli mediante las NCh 2676 y 2636 (2002). Salmonella, Staphylococcus aereus y Listeria monocytogenes utilizando NCh 2675, 2671 (2002) e ISO 11290-1: 1996 (rev 2004) y confirmadas por PCR. Cronobacter spp por medio de multilocus sequence typing (MLST) con criterios de http://www.pubmlst.org/cronobacter. Los requisitos de higiene del personal y expendio con listas de chequeo de acuerdo al RSA. Resultados: Las medianas globales de ENT fueron 30 000 000 UFC/g (2 000 000 - 300 000 000) y para E. coli de 450 UFC/g NMP/g (33 - 1 100), no existiendo diferencias significativas en los recuentos para ambos indicadores por marca y lugar de expendio (p>0.05). El cumplimento de requisitos de higiene del personal y expendio fue 50%. La positividad de L. monocytogenes fue 8.8%, no detectando Salmonella spp y S. aureus. Se aislaron 8 cepas sospechosas de Cronobacter spp las que fueron identificadas como Franconibacter helveticus. Conclusiones: Los quesillos evaluados no cumplen los criterios microbiológicos del RSA no siendo aptos para el consumo. La presencia de L. mono-cytogenes es un claro riesgo de salud en grupos de población hipersensible que consumen este alimento.

Objetivo. Evaluar la calidad microbiológica de algunos alimentos preparados y servidos en puestos ambulantes cercanos a universidades en Bogotá D.C. Materiales y métodos. Se realizaron recuentos de mesófilos aerobios, mohos y levaduras, Staphylococcus aureus, Bacillus cereus, esporas de Clostridium sulfito reductor, determinación de coliformes totales y fecales e investigación de Salmonella spp y Listeria monocytogenes. Resultados. Los hallazgos obtenidos en este estudio en Bogotá D.C califican a la mayoría de puestos de venta ambulatoria de alimentos con riesgo sanitario alto. Se requiere un mayor control por parte de las autoridades correspondientes y una mayor información y capacitación a vendedores y consumidores de este tipo de alimentos.

Objective. Determinate the microbiological quality of some prepared foods and served at stalls near universities in Bogota DC. Materials and methods. Mesophilic aerobic counts, molds and yeasts, Staphylococcus aureus, Bacillus cereus, sulfite reducing Clostridium spores, determination of total and fecal coliforms and investigation of Salmonella and Listeria monocytogenes were made. Results. The findings of this study in Bogota DC qualify most street vending stalls of foods high health risk. Need more control by the appropriate authorities and better information and training to sellers and consumers of these foods.

La vasculitis séptica es una inflamación de los vasos sanguíneos de pequeño y mediano calibre causada por la acción directa de agentes patógenos en el contexto de una sepsis. Es una condición infrecuente y se manifiesta clínicamente por lesiones cutáneas como púrpura, vesículo-pústulas e incluso úlceras. La mayoría de los casos de vasculitis séptica se asocian a una meningococcemia. No se han reportado casos en la literatura médica de vasculitis séptica secundaria a Listeria spp. Se presenta el caso de un hombre de 71 años, con cuadro de sepsis por Listeria monocytogenes y que presentó lesiones purpúricas con una biopsia compatible con una vasculitis séptica.

Septic vasculitis is a medium and small-vessel vasculitis caused by direct action of pathogens, associated with bacteremia. It is an uncommon condition; clinical manifestations include purpura, ulcers and vesicles-pustules. Most cases of septic vasculitis are related to meningococcemia. There are no cases reported in medical literature associated to Listeria spp. We report a case of a 71 year-old man who presented sepsis by Listeria monocytogenes, and then evolved with purpuric skin lesions. Skin biopsy revealed a septic vasculitis.

RESUMO No período de maio de 2008 a abril de 2009 foi avaliada a qualidade microbiológica de 40 amostras de queijo Minas Frescal produzidas artesanalmente e inspecionadas pelo Serviço de Inspeção Estadual e Federal no Município de Santa Helena, PR, através da quantificação do número mais provável de coliformes termotolerantes, contagem de Staphylococcus spp., pesquisa de bolores e leveduras, presença/ausência de Salmonella spp. e Listeria monocytogenes. Quanto à presença de coliformes termotolerantes, apresentaram-se em desacordo com o estabelecido pela ANVISA segundo a Resolução n° 12 de 02 de janeiro de 2001, 90% das amostras artesanais e 55% das inspecionadas. Em relação à enumeração de Staphylococcus spp., 100% das amostras artesanais e 25% das amostras inspecionadas apresentaram-se em desacordo com o estabelecido pela legislação. Salmonella spp. e Listeria monocytogenes não foram isoladas em 25 g do produto, mostrando que em relação a estes agentes as amostras de queijo analisadas, tanto de produção artesanal quanto as inspecionadas, apresentaram-se dentro dos padrões estabelecidos (ausência em 25 g do produto). Os resultados revelaram que, do total de amostras analisadas, somente 15% apresentaram-se de acordo com os padrões estabelecidos pela ANVISA, estando um número elevado de amostras artesanais (100%) e inspecionadas (70%) fora dos limites estabelecidos pela legislação. Portanto, maior atenção deve ser tomada pelas autoridades sanitárias, uma vez que tais produtos podem colocar em risco a saúde do consumidor.

ABSTRACT From May 2008 to April 2009 the microbiological quality of 40 samples of artisan-made cheeses and cheeses inspected by the State Inspection Service and Federal in Santa Helena, state of Paraná, Brazil, was evaluated by quantifying the most probable number of thermotolerant coliforms, count of Staphylococcus spp., research of yeasts and molds, and the determination of the presence/absence of Salmonella spp. and Listeria monocytogenes. In regard to the presence of thermotolerant coliforms, 90% of the artisan-made samples and 55% of inspected samples did not meet the standards established by ANVISA under Resolution Nº 12 dated 2 January 2001. In regard to the count of Staphylococcus spp., 100% of the artisan-made samples and 25% of the inspected samples did not meet the legal standards. Salmonella spp. and L. monocytogenes were not isolated in 25 g of the product, showing that for these agents the cheese samples analyzed, both the artisan made as well as the inspected production, were within the established standards (absence in 25 g of the product). The results revealed that of all the samples analyzed, only 15% were in accordance with the standards established by ANVISA, with a high percentage of artisan-made (100%) and inspected cheese (70%) outside the legal limits. Therefore, health authorities should pay more attention to this sector, since such products may endanger the health of consumers.

El objetivo del presente estudio fue evaluar la calidad bacteriológica de lechugas comercializadas en el Área Metropolitana de San José, Costa Rica y cultivadas de diversas maneras, con el fin de discernir diferencias entre los métodos de cultivo y el riesgo a la Salud Pública que estos productos pueden representar. El estudio se llevó a cabo en el Laboratorio de Microbiología de Alimentos de la Facultad de Microbiología, Universidad de Costa Rica, durante los meses de marzo a julio, 2010. Se analizaron 30 muestras de lechuga (10 cultivadas por el método tradicional, tradicional, 10 de cultivo orgánico y 10 producidas mediante hidroponía). Cada muestra fue adquirida en supermercados donde se certifica el origen de las mismas. A cada muestra se le determinó el recuento total de aerobios mesófilos aerobio, recuento de coliformes totales, fecales y de Escherichia coli, así como la presencia/ausencia en 25 g de Salmonella spp. y Listeria monocytogenes. Los resultados obtenidos demuestran que no existe una diferencia, estadísticamente significativa (p>0,001) entre los diferentes tipos de cultivo para ninguno de los parámetros evaluados. Un porcentaje importante de las muestras presentó colifomes, no obstante, únicamente se aisló una cepa de Escherichia coli, a partir de una lechuga cultivada de manera tradicional. Se logró aislar cuatro cepas de Salmonella spp así como una cepa de Listeria monocytogenes. Los datos obtenidos permiten evidenciar el hecho de que el consumo del producto crudo y sin una adecuada limpieza y desinfección representa un riesgo para la salud del consumidor, así como que no existe, desde el punto de vista bacteriológico, una diferencia significativa entre el cultivo tradicional, orgánico e hidropónico de la lechuga, lo que hace suponer que no se siguen los lineamientos específicos de cada tipo de cultivo, o se da un mal manejo y contaminación post cosecha en los productos.

The main objective of this work was to evaluate the microbiological quality of lettuces commercialized in the Metropolitan Area of San José, Costa Rica, and cultured in different ways, in order to detect differences between the culturing methods and the risk that these products may represent for Public Health. The study was done at the Food Microbiology Laboratory, Universidad de Costa Rica, from March to July, 2010. 30 lettuce samples were analyzed (10 obtained by traditional culture, 10 by organic culture and 10 by hydropony). All samples were obtained from markets where their origin was certified. Total aerobic plate count, total and fecal coliforms count and Escherichia coli were determined to all samples, as well as the presence/abscense of Salmonella spp. and Listeria monocytogenes in 25 g. Results obtained show that there is no statistically significant difference (pE. coli strain was isolated from a traditionally cultured lettuce sample. Four different Salmonella spp. strains were isolated from the samples as well as one Listeria monocytogenes strain. Data obtained show that the consumption of this product, raw or without an adequate hygiene and disinfection may represent a risk for health. Also, from the bacteriological point of view, there is no significant difference between the culturing methods evaluated, suggesting that the specific directions for each type of culture are not followed or that there is an inadequate handling of the products or post harvest contamination.

Introducción. La microbiota del tubo digestivo humano contiene bacterias benéficas para la salud que regulan el funcionamiento del colon e inhiben algunos microorganismos patógenos intestinales. Las bifidobacterias aisladas de neonatos y de leche materna se usan como microorganismos probióticos para prevenir enfermedades infecciosas, incluidas las transmitidas por alimentos. Objetivo. Aislar e identificar Bifidobacterium sp. en humanos y determinar su capacidad bactericida frente a patógenos causantes de enfermedades transmitidas por alimentos, importantes en Colombia y en el mundo. Materiales y métodos. Se recolectaron 17 muestras de leche materna, y 19 muestras de meconio y heces de neonatos, en diferentes hospitales de Bogotá. Los 26 aislamientos sospechosos se identificaron a nivel de género mediante PCR 16-23S; para la identificación de especie, se secuenciaron algunos de los aislamientos. La capacidad antagonista de las 26 cepas de Bifidobacterium sp. fue evaluada contra Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, Salmonella enteritidis ATCC 13076, Listeria monocytogenes ATCC 7644 y E. coli O157:H7 ATCC 35150. Para las cepas que presentaron mayor actividad antagonista, se analizó el extracto inhibidor con ensayos de difusión en placa. Resultados. Todas las cepas amplificaron la banda esperada para la confirmación de género; asimismo, las cepas Bif 013 y Bif 023 se identificaron por secuenciación como Bifidobacterium breve, con una homología del 97%. Del total de cepas, 17 mostraron capacidad de inhibir, al menos, uno de los patógenos evaluados. E. coli ATCC 25922 fue el patógeno más inhibido. Se determinó que la cepa Bif 023 es eficiente como antagonista, ya que inhibió todos los patógenos evaluados. Los halos de inhibición presentaron diámetros mayores a lo esperado, lo que indica una muy buena capacidad antagonista de las cepas nativas. Se aisló Bifidobacterium sp. de leche materna, meconio y heces de neonatos, por lo cual se confirmó que este microorganismo es microbiota humana (2). Conclusión. Se concluye que, debido a la gran capacidad antagonista de la mayoría de las bacterias aisladas, éstas pueden estar cumpliendo una importante función protectora en el recién nacido, en particular las cepas Bif 013 y Bif 023 aisladas de materia fecal. Estos microorganismos deben continuar siendo estudiados para definir su potencial probiótico. También, se pueden evaluar para bioconservación en la industria y contra patógenos transmitidos por alimentos.

Introduction. The microbiota in the human gastrointestinal tract contains beneficial microorganisms for human health, which contribute to the regulation of colonic function and inhibition of some intestinal pathogens growth. Bifidobacterium sp. isolated from newborns and breast milk are used as probiotic microorganisms, which are useful in the prevention of infectious diseases including foodborne illnesses. Objective: To isolate and identify human Bifidobacterium sp. and to determine its antibiotic activity against important pathogens which cause foodborne illnesses in Colombia and the world. Materials and methods. 17 breast milk samples and 19 meconium and newborn faeces samples were collected from different hospitals in Bogotá. 26 presumptive Bifidobacterium strains were identified at genus level by PCR 16-23S; some strains were identified at species level by nucleic acid sequencing. The antagonistic activity of 26 Bifidobacterium sp. strains was tested against Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, Salmonella enteritidis ATCC 13076, Listeria monocytogenes ATCC 7644 and E. coli O157:H7 ATCC 35150. For the strains that showed a greater antibiotic activity, the inhibitory compound was analyzed using disk diffusion tests. Results. All strains amplified the expected band for genus confirmation. Strains Bif 023 and Bif 013 were identified by DNA-sequencing as Bifidobacterium breve, with 97% homology. 17 strains were able to inhibit at least one of the pathogens tested. Escherichia coli ATCC 25922 was the most inhibited. It was determined that the strain Bif 023 is highly efficient as an antagonist strain due its ability to inhibit all the evaluated pathogens. Inhibition areas showed higher diameters than expected, suggesting an enhanced antagonist capacity of native strains. Bifidobacterium sp. was isolated from breast milk, meconium and newborn faeces which confirmed that this microorganism is human microbiota. Conclusion. Due to the high antagonist activity of most isolated bacteria, they could be playing an important protective function in the newborn, in particular strains Bif 013 and Bif 023, isolated from faeces. Other studies must be performed with these organisms to determine their probiotic potential as well as their use in the biocontrol industry due their activity against foodborne pathogens.

La reacción en cadena de la polimerasa, conocida como PCR, es un método que permite replicar miles de veces, en pocas horas e in vitro, pequeñas cantidades de ADN. La aplicación de métodos rápidos y sensibles, para detectar Listeria monocytogenes en muestras de queso blanco, permitirá un mejor control microbiológico del proceso de producción. Se aplicó PCR a 30 muestras de queso blanco, de una quesera de Valencia Estado Carabobo. Se detectó especificidad y sensibilidad para PCR mediante el empleo de la cepa control Listeria monocytogenes 446. Extracción de ADN según metodología descrita por Torres y col., Marcador de peso molecular de 100 pares de base. Se emplearon: cuatro cebadores del gen hlyA de listeriolisina O; iniciadores L1/U1 para banda 938 pb y LF/LR para banda 750 pb del gen hlyA. Estadístico EpiInfo V6 para concordancia de observaciones en geles, mediante coeficiente Kappa (K). Resultados: 8 de las 30 muestras de queso analizadas, mostraron crecimiento presuntivo de Listeria spp en Agar PALCAM. De las cuales 2 de las muestras no pertenecian al género Listeria; en las 6 restantes las pruebas de confirmación arrojaron que: 2 eran L. monocytogenes, 3 L.ivanovii y 1 L. seeligeri. Mediante PCR 2 muestras resultaron positivas para L. monocytogenes al amplificar la banda 938 pb para Listeria y banda 750 pb para la especie monocytogenes. Se concluye que PCR demostró ser altamente específico y sensible para L. monocytogenes, teniendo ventaja sobre agar PALCAM al evidenciar la presencia especifica del patógeno en un tiempo relativamente corto.

The Polymerase Chain Reaction, known as PCR, is a method to replicate thousands of times within a few hours and in vitro, small amounts of DNA. The application of rapid and sensitive methods to detect Listeria monocytogenes in cheese samples, allow a better microbiological control of the production process. PCR was applied to 30 samples of of white cheese, from Valencia, Carabobo State. It was detected PCR specificity and sensitivity by using the control strain Listeria monocytogenes 446. DNA extraction according to the methodology described by Torres et al., Molecular weight marker 100 base pairs. Were used: four primers hlyA gene of listeriolysin O; L1/U1 primers for 938 bp band and LF / LR 750 bp band hlyA gene. EpiInfo Statistical V6 to match observations in gels, by Kappa coefficient (K). Results: 8 out of 30 cheese samples analyzed showed presumptive growth of Listeria spp in PALCAM Agar. Two of the samples not belonged to the genus Listeria, in the 6 remaining sample confirmation tests showed that: 2 were L. monocytogenes, 3 L. ivanovii and 1 L. seeligeri. In PCR 2 samples were positive for L. monocytogenes by amplify the 938 bp band for Listeria and 750 bp band for the species monocytogenes. We concluded that PCR was highly specific and sensitive to L. monocytogenes, taking advantage of PALCAM agar to detect the presence of the pathogen specifies a relatively short time.

Se determinó la frecuencia de L. monocytogenes en tomates y cilantro, de tres diferentes supermercados, ubicados en el Municipio Valencia, Estado Carabobo, durante ocho semanas. Se evaluaron 192 muestras: 96 de tomates y 96 de cilantro. Procesamiento y análisis microbiológico, según Normas Industriales COVENIN 3718:2001. Paquete estadístico SPSS versión 12.0. Se aplicó prueba de Kolmogorov Smirnov, test de U Mann Whitney y Kruskal Wallis y correlación de Spearman. Nivel de significancia (pListeria spp para tomates y cilantro, durante las ocho semanas de recolección en los tres supermercados; ni tampoco entre las distribuciones de NMP en tomates y cilantro de los tres supermercados (Chi²=5,233 p2=1,624 p2=6,547 p2=2,667 pListeria spp en tomate fue 41,66% (25,0% L. monocytogenes y 16,7% L. ivanovii); en cilantro 77,08% (36,5% L. monocytogenes, 33,3% L. ivanovii, 7,3% L. seeligeri). Se concluye que el elevado porcentaje encontrado de L. monocytogenes en tomates y cilantro, es independiente del supermercado de expendio; se evidencia la necesidad de un control microbiológico a nivel del sistema de riego, recolección y distribución, para asegurar la calidad del producto.

The incidence of L. monocytogenes in tomatoes and coriander obtained from three different markets, during eight weeks were determined. 192 samples were evaluated: 96 of tomatoes, and 96 of coriander. The isolation of L. monocytogenes was performed using COVENIN 3718:2001. The data were analyzed by SPSS version 12.0. Kolmogorov Smirnov, Mann Whitney U, Kruskal Wallis U test; Spearman’s correlation were applied, and pListeria spp to tomatoes and coriander during the eight weeks of recollection in the markets; neither between the distributions of MPN of tomatoes and coriander from the markets (Chi²=5,233 p2=1,624 p2=6,547 p2=2,667 pL. monocytogenes and 16,7% L. ivanovii); in coriander 77,08% (36,5% L. monocytogenes, 33,3% L. ivanovii and 7,3% L. seelige.). We concluded that the high level of L. monocytogenes in tomatoes and coriander is independent of the markets store; we see the necessity of a microbiological control on the irrigation system, collection and distribution to ensure the quality of the product.

Introducción Listeria monocytogenes es un patógeno que puede transmitirse por el consumo de hortalizas, en Cuba no se conoce su incidencia en estos alimentos. Objetivos Evaluar la presencia de Listeria spp. y el efecto de los procedimientos de limpieza, en hortalizas frescas comercializadas en Ciudad de La Habana. Métodos Se estudió Listeria spp. en 86 muestras, mediante el método rápido de Oxoid (1999) y los métodos ISO 11290-1/1996 e ISO 11290-2/1998, se realizó enriquecimiento en frío y pruebas bioquímicas complementarias. Se determinaron indicadores de calidad sanitaria, coliformes (NC ISO 4832/2002) y coliformes fecales (NC 38-02-14/1989). Se comprobó la presencia o no de la bacteria después del proceso de limpieza, en muestras positivas a Listeria spp. y en muestras inoculadas con Listeria monocytogenes. Resultados En frijolitos chinos, lechuga, zanahoria, col y cebollino se detectó Listeria spp. por la prueba rápida; sólo en las tres últimas muestras se aisló L. innocua, en concentraciones <10²/g. Estas muestras presentaron coliformes >10³/g y dos de ellas, coliformes fecales >10²/g. Después del proceso de limpieza no se detectó la bacteria en cebollino y zanahoria positivos a L. innocua, mientras que en lechuga y zanahoria inoculadas con L. monocytogenes, sólo se redujo la carga microbiana. Se comprobó que no es suficiente el proceso tradicional de limpieza para eliminar L. monocytogenes a menos que se halle en bajas concentraciones. Conclusiones La única especie identificada fue L. innocua, que no constituye un riesgo para la salud. Las muestras positivas a Listeria spp. no poseen una buena calidad sanitaria.

Introduction Listeria monocytogenes is a pathogen that can be vegetable-borne. Its incidence on this type of food is unknown in Cuba. Objectives To evaluate the presence of Listeria spp. and the effect of cleaning methods in fresh vegetables on sale in the City of Havana. Methods Eighty six samples were analyzed by using Rapid Test Oxoid (1999) and the traditional ISO 11290-1 (1996) and ISO 11290-2 (1998) methods. Also additional biochemical tests and cold enrichment to 4 ºC, were made. Health quality indicators, coliforms (NC ISO 4832/2002) and faecal coliforms (NC 38-02-14/1989) were determined. The presence or absence of bacteria after the cleaning process was determined in samples positive to Listeria spp. and in contaminated samples with Listeria monocytogenes. Results Listeria spp. was detected by the rapid test in lettuce, carrot, cabbage and scallion; Listeria innocua was isolated in the last three ones at<10² UFC/g concentrations. These samples showed coliforms at>10³/g concentrations and two of them faecal coliforms at>10²/g. After the cleaning process, no bacteria was detected in previously L. innocua positive carrot and scallion samples whereas in lettuce and carrot samples innoculated with L. monocytogenes and cleaned, the level of this microorganism was just reduced. It was confirmed that the traditional cleaning process to eliminate L. monocytogenes is not enough unless this bacterium is present at low concentrations. Conclusions The only isolated species L. innocua was not a health risk. Listeria spp.-positive samples did not have good sanitary quality.