Pathogenicity of Fungi Isolated from Spoilt Sweet Oranges (Citrus sinensis) and from the Air in the Environment of the Orange Section of the Gamboru Market in Maiduguri, Nigeria

Aim: Though Oranges are very important crops for man both economically and in terms of nutrition, they have a short life span due to poor handling during harvesting, transporting, and storage. The ubiquitous nature of fungi makes them ready contaminants for these oranges especially when their skin is broken. The aim of this study is to isolate, identify and determine the pathogenicity of fungi responsible for spoilage in sweet oranges and investigate the presence of fungi in the air of the environment where these oranges are sold. Place and Duration of Study: Department of Microbiology Faculty of Science University of Maiduguri between September and October 2020. Methodology: A total of 100 samples of ripe oranges with signs of spoilage (n=100) were collected randomly from 10 selling points in the Gamboru fruit market in Maiduguri, Borno state of Nigeria, and analyzed for fungal isolates using morphometric techniques. Two mycological media Potato Dextrose Agar and Malt Extract Agar (PDA and MEA) were used for isolation, by deploying direct plating method. Petri dishes containing prepared PDA and MEA were also exposed to the air in the shops for some minutes. Morphometric analysis was carried out to identify the fungal isolates using macroscopic and microscopic observed features. Pathogenicity tests were carried out to ascertain the ability of these isolates to cause spoilage. Results: The results of the morphometric characterization revealed the presence of seven (Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger, and Penicillium oxalicum, Rhizopus oryzae, Cladiosporium sphaerospermum and Scopulariopsis brevicaulis) different fungi from the air and from the deteriorating oranges. Four of the isolates which were also positive for pathogenicity and observed to be responsible for causing spoilage in the oranges were also found to be the same as those isolated from the air, while three other organisms isolated from the air in the sales environment were not isolated from the spoilt oranges. Penicillium oxalicum was isolated from 41% of the oranges making it the most predominant organism causing spoilage in the oranges while Aspergillus fumigatus was isolated from only 10% of the samples. Conclusion: The findings of this study showed that fungal contaminants were responsible for the spoilage of oranges in this market and many of them were present in the air in the shops where these oranges were sold and stored leading to serious economic losses for both farmers and consumers.

Study of the Antioxidant and Immunomodulatory Activity of the Total Aqueous Extract of Clerodendrum splendens (G.Don) Leaves (Lamiaceae)

Post-harvest storage of oilseeds, particularly groundnut, is a real problem for farmers and traders whose stocks are subject to attacks by pests and fungal contaminants in the shops. In order to find alternative solutions to this problem, a survey was conducted in Côte d’Ivoire, specifically in the markets of the communes Abobo, Adjamé and Yopougon in city of Abidjan, Côte d’Ivoire. The objective of this work is to evaluate the main risk factors for spoilage of groundnut seeds sold during storage in the Abidjan markets. To this end, a survey was conducted among 75 groundnut seeds sellers in the three aforementioned communes of Abidjan and identified the main risk factors favorable to spoilage of groundnut seeds sold during storage. The lack of exact knowledge of the origin of the groundnut seeds sold (92 to 100%), the storage of groundnut seeds in polyethylene bags (84 to 100%), the lack of knowledge of spoilage (28 to 44%), the long periods of sale (22.2 to 86.7%), moisture (0 to 72.2%) and insect pests (5.6 to 20%° were identified as the main factors of these risk of spoilage.

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.

Purification, characterization, mode of action, and enhanced production of Salivaricin mmaye1, a novel bacteriocin from Lactobacillus salivarius SPW1 of human gut origin

Background: Emergence of antibiotic resistance among pathogenic and food spoilage bacteria such as Staphylococcus aureus, Micrococcus luteus, Streptococcus pyogenes, Streptococcus sanguinis, Streptococcus mutans, Bacillus cereus, and Listeria monocytogenes triggered the search for alternative antimicrobials. An investigation aimed at purifying, characterizing, elucidating the mode of action, and enhancing the production of salivaricin from Lactobacillus salivarius of human gut origin was conducted. Results: Salivaricin mmaye1 is a novel bacteriocin purified from L. salivarius isolated from human feces. It is potent at micromolar concentrations and has a molecular weight of 1221.074 Da as determined by MALDI-TOF mass spectrometry. It has a broad spectrum of antibacterial activity. Salivaricin mmaye1 showed high thermal and chemical stability and moderate pH stability. The proteinaceous nature of salivaricin mmaye1 was revealed by the complete loss of activity after treatment with pepsin, trypsin, α-chymotrypsin, protease, and proteinase. Salivaricin mmaye1 is cell wall associated, and adsorption­desorption of the bacteriocin from the cell wall of the producer by pH modification proved successful. It exhibited a bactericidal mode of action mediated by pore formation. Its biosynthesis is regulated by a quorum sensing mechanism. Enhanced production of salivaricin mmaye1 was achieved in a newly developed growth medium. Conclusions: A novel, cell wall adhering, highly potent bacteriocin with a broad spectrum of inhibitory activity, membrane-permeabilizing ability, and enhanced production in a newly constituted medium has been isolated. It has a quorum sensing regulatory system and possesses interesting physicochemical characteristics favoring its future use in food biopreservation. These findings pave the way for future evaluation of its medical and food applications.

Proteolytic and lipolytic potential of Pseudomonas spp. from goat and bovine raw milk / Potencial proteolítico e lipolítico de espécies de Pseudomonas do leite cru caprino e bovino

Pseudomonas, the main genus of gram-negative microorganisms isolated from milk, is psychrotrophic, biofilm-forming, and thermo-resistant deteriorating enzyme producers. The aim of this study was to quantify Pseudomonas spp. in goat's and cow's milk produced in the Paraná state, Brazil, to evaluate the deteriorating activity of the isolates at mesophilic and psychrotrophic conditions and to identify, at the species level, the isolates with alkaline metalloprotease (aprX gene) production potential. Microbiological, biochemical and molecular methods were used for isolating, confirming and identifying of isolates. The mean counts were 1.6 (±6.3)x104 and 0.89(±3)x102 CFU/mL for goat and bovine milk samples, respectively, immediately after milking. Of the Pseudomonas colonies isolated from goat milk (n=60), 91.7% showed proteolytic potential when incubated at 35°C/48 h and 80% at 7°C/10 days, and lipolytic potential was observed in 95% of the isolates incubated in mesophilic and 78.3% at refrigeration conditions. From the isolates of bovine milk (n=20), 35% showed proteolytic activity only when incubated at 35°C/48 h, and lipolytic potential was observed in 25% of the isolates incubated at 7°C/10d and 35°C/48h. It was observed that 83.3% and 25% of the isolates genetically confirmed as Pseudomonas spp. of goat and bovine milk showed the potential for alkaline metalloprotease production, with the species P. azotoformans, P. koreensis, P. gessardii, P. monteilii and P. lurida being the most frequent in goat milk and P. aeruginosa the only species identified in cow milk.(AU)

Pseudomonas é o principal gênero de micro-organismos Gram negativos isolados do leite, são psicrotróficos, formadores de biofilmes e produtores de enzimas deteriorantes termodúricas. O objetivo do presente trabalho foi quantificar Pseudomonas spp. no leite de cabras e vacas produzido no estado do Paraná, Brasil, avaliar a atividade deteriorante em temperatura mesofílica e psicrotrófica e identificar, em nível de espécie, os isolados com potencial de produção de metaloprotease alcalina (geneaprX). Foram utilizados métodos microbiológicos, bioquímicos e moleculares para isolamento, confirmação e identificação dos isolados. As contagens médias foram de 1,6 (±6,3) x 104 e 0,9 (±3) x 102 UFC/mL para as amostras de leite caprino e bovino, respectivamente. Dos isolados de Pseudomonas do leite de cabra (n=60), 91,7% demonstraram potencial proteolítico quando incubadas a 35°C/48h e 80% a 7°C/10dias e lipolíticos em 95% dos isolados incubados em mesofilia e em 78,3% dos incubados em temperatura de refrigeração. Dos isolados do leite bovino (n=20), foi verificada atividade proteolítica de 35% apenas quando incubadas a 35°C/48h e lipolítica em 25% dos isolados incubados a 7°C/10d e 35°C/48h. Foi observado que 83,3% e 25% dos isolados confirmados geneticamente como Pseudomonas spp. do leite caprino e bovino, respectivamente, apresentaram o potencial de produção de metaloprotease alcalina, sendo as espécies P. azotoformans, P. koreensis, P. gessardii, P. monteilii e P. lurida as mais frequentes no leite de cabras e P. aeruginosa a única identificada do leite de vacas.(AU)

Isolation, Identification and Pathogenicity of Fungal Organisms Causing Postharvest Spoilage of Tomato Fruits during Storage

Isolation, identification and pathogenicity of fungal organisms causing postharvest spoilage of tomato fruits during storage was carried out. Tomato fruits showing symptoms of rot were collected from the store house. Small sizes were cut and surface sterilized in 1% of Sodium hydrochloride and rinsed in several changes of sterile distilled water. They were plated on Potato Dextrose Agar (PDA) and observed for fungal growth. Identification was done macroscopically and microscopically. For pathogenicity, healthy tomato fruits were plugged with pure cultures of the fungal isolates and disease incidence and severity were evaluated. Five fungi namely Aspergillus flavus, Penicillium waksmanii, Botryodiplodia theobromae, Fusarium oxysporum and Colletotrichum asianum were isolated. Incidence of decay on healthy tomato fruits was 100% for all fungal isolates while the control was 0%. T-test revealed significant differences between the inoculated and the controls at 1% and 5% levels of probability. Severity of decay ranged from 51–53% for all fungal isolates, while the controls showed 0%. T-test revealed significant differences between the inoculated and the control at 1% and 5% levels of probability. Pathogenic microorganisms on tomato are a potential health hazard to man and animals following ingestion.

Development of a quality index scheme and shelf-life study for whole tambaqui (Colossoma macropomum) / Desenvolvimento do protocolo do Índice de Qualidade e estudo da vida útil do tambaqui

ABSTRACT The study developed a sensory scheme based on the Quality Index (QI) and estimated the shelf-life for whole tambaqui, Colossoma macropomum (Cuvier, 1818), stored in ice, assessing and determining the most appropriate chemical, physical, bacteriological and quality sensory parameters and their changes during storage time. Ninety six fish were evaluated at 1, 3, 5, 8, 10, 12, 15, 17, 19 and 22 days of ice-storage. The developed quality index (QI) showed four main quality attributes with a total of 29 demerit scores. The skin mucus and odor, as well as general appearance and ventral elasticity had a great importance for the statistical model applied, while eyes, gill mucus and dorsal elasticity showed lower significance for tambaqui QI. The pH showed few variations during the ice storage. Nitrogen bases, as well as the total count of specific spoilage bacteria, had a linear correlation with storage time. The QI proved to be efficient to assess tambaqui quality and loss of sensory quality over the storage period. The results suggest that whole, ice-stored Colossoma macropomum is fit for consumption until the 22nd day.

RESUMO O estudo desenvolveu um protocolo sensorial baseado no Método do Índice de Qualidade (IQ), estimando a vida útil do tambaqui, Colossoma macropomum, inteiro e conservado em gelo, avaliando e determinando as principais alterações físico-químicas, microbiológicas, os parâmetros sensoriais e suas alterações durante o armazenamento em gelo. Noventa e seis peixes foram avaliados no dia 1, 3, 5, 8, 10, 12, 15, 17, 19 e 22 de armazenamento em gelo. O índice de qualidade desenvolvido (IQ) apresentou quatro principais atributos de qualidade com um total de 29 pontos de demérito. O muco e odor da pele, assim como a aparência geral e elasticidade ventral, apresentaram uma maior importância para o modelo estatístico aplicado, enquanto que os olhos, muco das brânquias e elasticidade dorsal mostraram menor significância para o IQ do tambaqui. O pH apresentou poucas variações durante o armazenamento em gelo. As bases nitrogenadas voláteis totais, bem como a contagem total de bactérias específicas de deterioração, apresentaram correlação linear com o tempo de armazenamento. O IQ mostrou-se eficiente para avaliar a qualidade do tambaqui e as perdas da qualidade sensorial ao longo do período de armazenamento. Os resultados sugerem que o tambaqui, Colossoma macropomum, inteiro e conservado em gelo é considerado adequado para consumo até o 22° dia de armazenamento.

Antimicrobial activity of different sodium and potassium salts of carboxylic acid against some common foodborne pathogens and spoilage-associated bacteria / Actividad antimicrobiana de diferentes sales de ácidos carboxílicos de sodio y potasio contra algunos microorganismos patógenos y de deterioro asociados a alimentos

Cleaning and disinfection represent the most important activities associated with the elimination of dirt and microorganisms at food processing plants. Improper procedures may lead to cross contamination of food leading to its spoilage or even the transmission of foodborne pathogens. Several strategies have been used in order to achieve a good disinfection of sursalts; faces and products; nevertheless, microbial resistance to common-use-products has developed Potassium lately. Due to this fact, the development of new non-toxic-food compatible chemical agents that reduce the impact of foodborne pathogens and spoilage causing microorganisms is desirable for the food industry. The objective of the present study was to evaluate the antimicrobial activity of different sodium and potassium salts of aliphatic and aromatic carboxylic acid on the growth of common food spoilage and pathogenic microorganisms. Growth curves were determined for Leuconostoc mesenteroides, Lactobacillus plantarum, Enterococcus faecalis, Candida albicans, Pseudomonas aeruginosa, Salmonella Enteritidis, and Listeria monocytogenes in contact with different concentrations of carboxylic acid salts. The inhibitory effect of both aliphatic and aromatic carboxylic acid salts, in accordance with concentration levels, was 100 > 50 > 25 mg/ml. The inhibitory effect of aliphatic salts was butanoic > hexanoic> octanoic > decanoic and, benzoic > gallic > caffeic acid salts for aromatic salts. In general, sodium salts were more inhibitory than potassium salts (p < 0.05).

La limpieza y la desinfección representan las actividades más importantes asociadas a la eliminación de suciedad y microorganismos de las plantas procesadoras de alimentos. El uso de procedimientos incorrectos puede llevar a la contaminación cruzada de los alimentos y, por ende, al deterioro de estos o a la transmisión de patógenos de origen alimentario. Se han desarrollado varias estrategias con el fin de obtener una buena desinfección de superficies y productos; no obstante, ha aparecido resistencia microbiana frente a productos de uso común. Debido a esto, el desarrollo de agentes químicos no tóxicos capaces de reducir el impacto de patógenos de origen alimentario y microorganismos causantes de deterioro es deseable para la industria alimentaria. El objetivo de este estudio fue evaluar la actividad antimicrobiana de diferentes sales de sodio y potasio de ácidos carboxílicos alifáticos y aromáticos sobre algunos microorganismos patógenos y asociados a deterioro alimentario, analizando su impacto sobre el crecimiento. Se determinaron las curvas de crecimiento de Leuconostoc mesenteroides, Lactobacillus plantarum, Enterococcus faecalis, Candida albicans, Pseudomonas aeruginosa, Salmonella enteritidis y Listeria monocytogenes en presencia de diferentes concentraciones de las sales de ácidos carboxilicos. El efecto inhibitorio de las sales de ácidos carboxilicos alifáticos y aromáticos, según su nivel de concentración, se ordenó del siguiente modo: 100mg/ml > 50mg/ml > 25 mg/ml. El efecto de las sales de ácidos alifáticos siguió el orden butanoico > hexanoico > octanoico > decanoico, en tanto que las de ácidos aromáticos se ordenó del siguiente modo: benzoico > gálico >cafeico. En general, las sales de sodio fueron más inhibitorias que las de potasio (p < 0,05).

Spoilage potential of psychrotrophic bacteria isolated from raw milk and the thermo-stability of their enzymes / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

The storage and transportation of raw milk at low temperatures promote the growth of psychrotrophic bacteria and the production of thermo-stable enzymes, which pose great threats to the quality and shelf-life of dairy products. Though many studies have been carried out on the spoilage potential of psychrotrophic bacteria and the thermo-stabilities of the enzymes they produce, further detailed studies are needed to devise an effective strategy to avoid dairy spoilage. The purpose of this study was to explore the spoilage potential of psychrotrophic bacteria from Chinese raw milk samples at both room temperature (28 °C) and refrigerated temperature (7 °C). Species of Yersinia, Pseudomonas, Serratia, and Chryseobacterium showed high proteolytic activity. The highest proteolytic activity was shown by Yersinia intermedia followed by Pseudomonas fluorescens (d). Lipolytic activity was high in isolates of Acinetobacter, and the highest in Acinetobacter guillouiae. Certain isolates showed positive β-galactosidase and phospholipase activity. Strains belonging to the same species sometimes showed markedly different phenotypic characteristics. Proteases and lipases produced by psychrotrophic bacteria retained activity after heat treatment at 70, 80, or 90 °C, and proteases appeared to be more heat-stable than lipases. For these reasons, thermo-stable spoilage enzymes produced by a high number of psychrotrophic bacterial isolates from raw milk are of major concern to the dairy industry. The results of this study provide valuable data about the spoilage potential of bacterial strains in raw milk and the thermal resistance of the enzymes they produce.

Modelling the growth of lactic acid bacteria at different temperatures

ABSTRACT Mathematical models are widely used to predict the shelf life of foods. Lactic acid bacteria (LAB), particularly Lactobacillus plantarum, Weissella viridescens and Lactobacillus sakei, are the main spoilage bacteria of refrigerated, vacuum-packed meat products, stored in modified atmosphere, and their growth determines the shelf life length of these products. The objective of this study was to model the growth of L. plantarum, W. viridescens and L. sakei under different isothermal cultivation conditions and establish secondary models to describe the effect of temperature on the growth parameters of these bacteria. The LAB growth was evaluated in culture medium at temperatures of 4, 8, 12, 16, 20 and 30 ºC. The fit of Baranyi and Roberts (BAR) and Gompertz (GO) primary models to the growth curves of LAB was compared by statistical indices, in which the BAR model showed slightly better fits to the experimental data. The BAR growth parameters were used to establish the secondary models, µmax and Nmax were established for the three LAB. The power model described the influence of temperature on the parameter λ for L. plantarum, and other bacteria showed no lag phase. The growth of LAB was strongly influenced by storage temperature and the obtained models allow predicting the growth of these bacteria within the temperature range from 4 to 30 ºC.

Modelo de predicción probabilística de deterioro en jamón de cerdo cocido / Probabilistic prediction model of deterioration of pork cooked ham

Antecedentes: el deterioro del jamón cocido es un proceso complejo que puede manifestarse por alteraciones de tipo microbiológico, fisicoquímico y sensorial, que hasta hoy han sido determinadas por metodologías tradicionales que incluyen largos periodos de seguimiento y un número importante de muestras. Objetivos: en el presente estudio se propuso un modelo para la predicción probabilística del deterioro de jamón cocido, por medio de análisis de componentes principales (ACP) y regresión logística con aproximación bayesiana. Métodos: para realizar el análisis, se evaluaron muestras provenientes de 300 lotes independientes de jamón de cerdo cocido, los cuales se conservaron en cámaras de almacenamiento a temperaturas de 12±1°C. Se determinaron experimentalmente tres tipos de variables: fisicoquímicas (pH, sinéresis, nitritos residuales, porcentaje de ácido láctico), de textura (adhesividad, dureza, trabajo de punción y firmeza instrumental) y microbiológicas (mesófilos aerobios y bacterias acidolácticas) en dos tiempos de medición: 3 y 40 días. Para realizar la creación del modelo se seleccionaron aleatoriamente el 60% de los datos y para la validación el 40% restante. Los datos obtenidos fueron procesados con el paquete estadístico R Core Team 2012. Resultados: los nitritos residuales y la sinéresis fueron las variables más representativas, ya que su distribución, correlación y carga, fueron las más significativas, con mayor poder discriminante del fenómeno de deterioro en los dos momentos de medición. El modelo desarrollado permitió correlacionar los parámetros estudiados y predecir la probabilidad de deterioro del jamón, además de clasificarlo de acuerdo a su estado de calidad. La primera componente principal (CP1) (variables bioquímicas) explicó el 73,3 % de la variación total de los datos, siendo los nitritos residuales y la sinéresis los factores más relacionados con el deterioro. Conclusión: el modelo logístico con aproximación bayesiana permitió obtener la probabilidad de deterioro del jamón cocido, almacenado a 12°C usando parámetros fisicoquímicos. La aplicación del ACP permitió correlacionar y clasificar los factores de deterioro del producto.

Background: the spoilage of cooked ham is a complex process that may be manifested by alterations of microbiological, physicochemical and sensory type, which has been determined by traditional methodologies including long periods of monitoring with a significant number of samples. Objective: in the present study a model for probabilistic prediction of spoilage of cooked ham was proposed by principal component analysis (PCA) and logistic regression with Bayesian approach. Methods: to perform the analysis, independent samples from 300 batches of cooked pork ham were evaluated, which were stored in cold at temperatures 12 ± 1°C. Three types of variables were experimentally determined: physicochemical (pH, syneresis, residual nitrite, lactic acid percentage), texture (adhesiveness, toughness, puncture and instrumental firmness) and microbiological (aerobic mesophilic bacteria and lactic acid bacteria) in two times: 3 and 40 days. To make this model were randomly selected 60% of the data and to validate it the remaining 40%. The obtained data were processed with statistical package R package statistical Core Team 2012. Results: residual nitrite and syneresis were the most representative variables, since its distribution, correlation and loadings were the most significant, more discriminant of the phenomenon of spoilage in the two times of measurement. The developed model allowed correlating the parameters and predicting the spoilage probability of cooked ham, and classifying them according to their quality status. The first principal component (PC1) (biochemical variables) explained 73.3 % of the total variation, the residual nitrite and syneresis were the factors that related the spoilage. Conclusions: the logistic regression model with Bayesian approach allowed obtaining the probability of deterioration of cooked ham, stored at 12°C using physicochemical parameters. Applying the PCA permited to correlate and classify the factors of spoilage.

Development of a propidium monoazide-polymerase chain reaction assay for detection of viable Lactobacillus brevis in beer

ABSTRACT The spoilage of beer by bacteria is of great concern to the brewer as this can lead to turbidity and abnormal flavors. The polymerase chain reaction (PCR) method for detection of beer-spoilage bacteria is highly specific and provides results much faster than traditional microbiology techniques. However, one of the drawbacks is the inability to differentiate between live and dead cells. In this paper, the combination of propidium monoazide (PMA) pretreatment and conventional PCR had been described. The established PMA-PCR identified beer spoilage Lactobacillus brevis based not on their identity, but on the presence of horA gene which we show to be highly correlated with the ability of beer spoilage LAB to grow in beer. The results suggested that the use of 30 µg/mL or less of PMA did not inhibit the PCR amplification of DNA derived from viable L. brevis cells. The minimum amount of PMA to completely inhibit the PCR amplification of DNA derived from dead L. brevis cells was 2.0 µg/mL. The detection limit of PMA-PCR assay described here was found to be 10 colony forming units (CFU)/reaction for the horA gene. Moreover, the horA-specific PMA-PCR assays were subjected to 18 reference isolates, representing 100% specificity with no false positive amplification observed. Overall the use of horA-specific PMA-PCR allows for a substantial reduction in the time required for detection of potential beer spoilage L. brevis and efficiently differentiates between viable and nonviable cells.

Comportamento dos micro-organismos indicadores frente ao chapoteo na produção de polpa de camu-camu / Behavior of micro-organisms in the presence of splashes in the production of camu-camu pulp

O Chapoteo é uma nova etapa de processo estabelecida na produção de polpa de camu-camu, com a finalidade de obter um produto com melhor atributo de cor, vitamina C e sabor. Tendo em conta que esta etapa usa calor, os objetivos desta pesquisa foram: conhecer o efeito que tem o Chapoteo a nível industrial sobre a carga de Micro-organismos Indicadores da Alteração (MIA), e comparar essa carga com a obtida no Processo Convencional de Extração Mecânica (PCEM), antes da pasteurização. Os resultados mostraram que após o Chapoteo, todas as contagens para os grupos de micro-organismos avaliados estiveram abaixo de 100 UFC/g, sendo muito inferiores aos valores obtidos no PCEM. O Chapoteo demonstrou que pode reduzir significativamente a contagem de MIA, não sendo necessária a aplicação de uma etapa posterior de tratamento térmico no processamento de polpa de camu-camu.(AU)

Parâmetros microbiológicos em diferentes cortes de carne bovina resfriada / Microbiological parameters in different cuts of cooled beef

O objetivo deste estudo foi verificar a contagem de mesófilos, coliformes totais, Staphylococcus aureus, Escherichia coli e presença de Salmonella sp. em cortes de traseiro de bovinos obtidos em um abatedouro frigorífico sob Inspeção Federal. Os resultados indicaram que todos os cortes mostraram-se ausentes para Salmonella sp. e a maior média de contagem para mesófilos foi no Filé de costela, seguido pela Picanha, Coxão mole, Fralda, Pera (recorte do Coxão Mole) e Maminha. Destes, a Pera e a Picanha apresentaram os maiores valores para Staphylococcus aureus. As maiores médias de contagens em UFC/g para coliformes totais foram nos cortes: Coxão mole, Alcatra, Pera e Filé-Mignon. De forma geral, os níveis de coliformes totais foram baixos, porém revelaram a presença de Escherichia coli principalmente no Coxão Mole. A Alcatra apresentou resultados elevados para coliformes totais, porém, sem a presença de E. coli. Os resultados dos cortes coletados mostraram que não houve desvio aparente nos processos quanto às operações do abate, a desossa e refile.

The aim of this study was to verify the mesophilic count, total coliforms, Staphylococcus aureus, Escherichia coli and the presence of Salmonella sp. in cattle rear cuts obtained in a slaughterhouse governed under Federal Inspection. The results indicated that all the cuts proved to be absent for Salmonella sp. and the highest average count for mesophilic was in rib steak, followed by Top Sirloin Cap, Topside, Flank Steak, Cut of Topside and Tenderloin. Of these, Cut of Topside and Top Sirloin Cap showed the highest values for S. aureus. The highest average scores in CFU/g for total coliforms were in cuts: Topside, Rump Steak, Cut of Topside and Tenderloin. The levels of total coliforms were low and showed the presence of Escherichia coli in the Topside. The results showed high thighs of coliforms, but without the presence of E. coli. The results of the collected cuttings showed no apparent shift in processes and operations during slaughter and boning and trimming.

Comparative proteome analysis of Brettanomyces bruxellensisunder hydroxycinnamic acid growth

Background: Brettanomyces bruxellensis is an important spoilage yeast in the winemaking process. The capacity of this yeast to generate an undesired off-flavor constitutes a significant loss in the Chilean wine industry. Results: The proteomic profile of B. bruxellensis in the presence of p-coumaric acid was determined by 2D gel electrophoresis, gel image analysis and differential spot selection. A set of 41 proteins showed a differential accumulation of ±2 and a p-value <0.0001. The homology sequence analysis was performed using the databases available. Differential proteins belonged to the categories of 'energy production and conversion' and 'amino acid transport and metabolism'. Conclusions: The proteomic profile of B. bruxellensis cultivated in the presence of p-coumaric acid in synthetic wine, agrees with the hypothesis of metabolic flux regulation, allowing a better conditioning to an adverse environment. This study involved the translational level of B. bruxellensis in the production of ethylphenols and corroborated that this yeast presented an advantage in these stress conditions. Thus, this work will allow an understanding of the regulation and processes involved in the production of ethyl-derivate compounds by B. bruxellensis. Furthermore, it allows the development of newer and better techniques for spoilage yeast control.

Characterization of the spoilage lactic acid bacteria in “sliced vacuum-packed cooked ham”

The lactic acid bacteria are involved with food fermentation and in such cases with food spoilage. Considering the need to reduce the lactic acid bacteria growth in meat products, the aim of this work was to enumerated and investigated the lactic acid bacteria present on sliced vacuum-packed cooked ham stored at 4 °C and 8 °C for 45 days by phenotypic and molecular techniques. The quantification showed that the lactic acid bacteria were present from the first day with mean count of 1.98 log cfu/g for the four batches analyzed. The lactic acid bacteria grew rapidly on the samples, and plate counts around 7.59 log cfu/g and 8.25 log cfu/g were detected after 45 days of storage at 4 °C and 8 °C, respectively; storage temperatures studied showed significant influence on the microorganism in study growth. The predominant lactic acid bacteria associated with the spoilage samples at one day of storage includes Lactobacillus sp., the phenotypic overlap Leuconostoc/Weissella sp. and Enterococcus sp. At 45 days of storage at 4 and 8 °C the mainly specie was Lactobacillus curvatus, following by Lactobacillus sakei and Leuconostoc mesentereoides; the Enterococcus sp. was not present in the samples.

Histamine content in local consumers demanded fishes of Tuticorin.

Histamine is a biogenic amine, which is developed in protein rich food as a result of histidine decomposition and this decomposition is caused by growth of certain types of bacteria. The biogenic amine of histamine content is an essential quality parameter in sea food quality and strict upper limits on acceptable levels have been introduced in US and EU markets. The present work addressed histamine content of the local consumers demanded fishes from local fish market, street vendors and from the fish landing centers. The results showed higher histamine development was observed in sea foods from street vendors followed in the fishes in the local fish market. Slow histamine development observed in sea foods from the landing centers. The results revealed that, histamine development in sea foods depends upon the quality of the sea food and fishes exposed longer time to the environment is possible for the development of biogenic amines.

Coriander (Coriandrum sativum L.) essential oil: Chemistry and biological activity

Coriandrum sativum L. (C. sativum) is one of the most useful essential oil bearing spices as well as medicinal plants, belonging to the family Umbelliferae/Apiaceae. The leaves and seeds of the plant are widely used in folk medicine in addition to its use as a seasoning in food preparation. The C. sativum essential oil and extracts possess promising antibacterial, antifungal and anti-oxidative activities as various chemical components in different parts of the plant, which thus play a great role in maintaining the shelf-life of foods by preventing their spoilage. This edible plant is non-toxic to humans, and the C. sativum essential oil is thus used in different ways, viz., in foods (like flavouring and preservatives) and in pharmaceutical products (therapeutic action) as well as in perfumes (fragancias and lotions). The current updates on the usefulness of the plant C. sativum are due to scientific research published in different web-based journals.

Technological Properties of Lactococcus lactis subsp. lactis I23 Isolated from Nigerian Beef and Characterization of Bacteriocin Produced by It.

Aim: The present study reports the phenotypic and molecular characterization of Lactococcus strains isolated from Nigerian beef. The technological properties of selected strains were evaluated in order to test their suitability as candidates of starter cultures for food preservation. Study Design: Experimental microbiological testing. Place and Duration of Study: Microbiology Department, University of Ibadan, Nigeria and Division of Food Sciences, The University of Nottingham, UK; between January 2005 and February 2009. Methodology: Phenotypic method was adopted in the initial characterization of the presumptive Lactococcus strains which were later characterized using pulsed field gel electrophoresis. The use of 16S rDNA sequencing was adopted in the full identification of selected strains. High performance liquid chromatography and Gas chromatography were employed in determining production of organic acids and diacetyl respectively by the strains of Lactococcus. Testing and identification of bacteriocin production by the strains were observed using in vitro and polymerase chain reaction methods. The antimicrobial activities of the strains were evaluated against known spoilage and pathogenic organisms of food origin. Results: Three strains, Lc. lactis L11, Lc. lactis subsp. lactis I23 and Lc. lactis subsp. hordinae E91 showed better production of diacetyl and lactic acid than others; concentrations in excess of 31.15 μg/10-7cfu and 17.56 g/107cfu at 18 and 24 h of incubation were recorded for the respective compounds. Result of their antimicrobial activities indicates that varying levels of inhibition were recorded against the spoilage/pathogenic organisms; however no inhibition was recorded against Brochothrix thermosphacta except by Lc. lactis subsp lactis I23 which was shown to encode gene for production of bacteriocin, nisin. The nucleotide sequence of the bacteriocin was deposited at the genBank under accession number EU667387. Conclusion: The ability of the three Lactococcus strains to combat spoilage and pathogenic organisms could help promote safety in food processing and preservation in Nigeria; moreover, production of bacteriocin by Lc. lactis subsp. lactis I23 may confer added advantage during choice of candidacy for starter cultures in food biopreservation.

Efecto de la inclusión de una fuente de fibra dietaria sobre la degradación lipídica y proteica de un producto cárnico tipo hamburguesa / Effect of adition of plantain dietary fiber on lipid and protein spoilage in a hamburger-like meat product

A source of dietary fiber obtained from plantain peel (Musa AAB) was characterized in terms of dietary fiber, total phenols and antioxidant capacity in order to generate proposal for use of the byproducts of plantain agribusiness. Thereafter, the effect of the inclusion of the source of dietary fiber was evaluated at levels of0 g, 5.5 g, y 6.5 g (treatment) of adding source of dietary fiber /100 g in a hamburger-type meat product during a time period of 28 days (with sampling on days 0, 7, 14, 21 and 28) on lipid and protein spoilage in terms of malonaldehyde production per gram of meatproduct and volatile nitrogenous bases per 100 g of meat product. Treatments including dietary fiber had no significant effect on lipid degradation (p>0.05) while protein degradation had statistically significant differences (p<0.05), volatile nitrogenous bases values were lower on treatments with 5.5, y 6.5 g of adding source of dietary fiber /100 g in a hamburger. It is concluded that the high fiber source obtained from dietary plantain peels by applied process may be used to increase hamburger's dietary fiber level and to prevent protein degradation.

Con el objetivo de generar una propuesta de aprovechamiento de los subproductos de la agroindustria del plátano, en esta investigación se caracterizó una fuente de fibra dietaria obtenida a partir de cáscara de plátano (Musa AAB) en términos de fibra dietaria, fenoles totales y capacidad antioxidante; posteriormente se evaluó el efecto de la inclusión de la fuente de fibra dietaria a niveles de 0 g, 5,5 g, y 6,5 g de inclusión de la fuente de fibra dietaria /100 g de producto cárnico tipo hamburguesa (tratamientos) durante un periodo de tiempo de 28 días (con muestreos los días 0, 7, 14, 21 y 28) sobre la degradación lipídica y proteica en términos de producción de malonaldehído por gramo de producto cárnico (hamburguesa) y bases nitrogenadas volátiles por cada 100 g de producto cárnico tipo hamburguesa. Los tratamientos con inclusión de fibra dietaria no tuvieron efecto significativo sobre la degradación lipídica (p>0,05) mientras que en la degradación proteica sí se presentaron diferencias estadísticamente significativas (p<0,05) siendo menores los valores de bases nitrogenadas volátiles obtenidos de los tratamientos con 5,5 g, y 6,5 g de inclusión de la fuente de fibra dietaria /100 g de hamburguesa. Se concluye que la fuente de fibra dietaria obtenida a partir de cáscara de plátano mediante el proceso aplicado, puede utilizarse para aumentar el nivel de fibra dietaria en un producto cárnico tipo hamburguesa y para obtener un efecto protector sobre la fracción proteica del producto cárnico.