Correlation between natural microbial load and formation of ropy slime affecting the superficial color of vacuum-packaged cooked sausage.

The present study outlines a comprehensive correlation between the natural microbial load, which is predominantly composed of heat-resistant sporous-forming Bacillus, and the changes in the original properties related to the superficial color of vacuum-packaged cooked sausages. For this purpose, microbial growth curves were plotted by stimulating the growth of the natural microbiota in sausage packages at different temperatures. The correlations were investigated during sample incubation by the instrumental evaluation of color and the ropy slime detection on the sausage surface. The entrance of the natural microbiota into the stationary phase (ca. 9.3 log cfu/g) resulted in changes in the superficial color, which was demonstrated by the discoloration of vacuum-packaged cooked sausages. Therefore, it seems to be a suitable borderline for predictive models applied in durability studies that aim to estimate the period in which vacuum-packaged cooked sausages keep their typical superficial color, anticipating product refusal in markets.

Fat replacement by green banana biomass: Impact on the technological, nutritional and dynamic sensory profiling of chicken mortadella.

Reducing the fat content of processed meat products has become necessary due to consumer-driven demand for healthier foods. In this sense, this study aimed to characterize chicken mortadella with total and partial replacement of chicken skin by green banana biomass (GBB). Five treatments (with two repetitions each and weighing 400 g) were prepared: F0 (control treatment formulated with 100% chicken skin), F1, F2, F3, and F4 (25, 50, 75, and 100% of chicken skin replacement by GBB, respectively). Samples were characterized according to physicochemical composition - approximate composition, energy value, pH, water activity (Aw), emulsion stability (ES), water-holding capacity (WHC), instrumental color (L*, a* and b*), instrumental texture, fatty acid profile, and microstructure) - nutritional quality and sensory properties (dynamic profiling by Temporal Check-all-that-apply and acceptance). The replacement of 100% chicken skin by GBB increased the WHC of mortadella and did not affect the ES in all formulations. The addition of GBB did not affect the typical mortadella flavor of the samples, and the dominance of the flavor was directed towards the fibrous and fat flavor attributes. In addition, all formulations had acceptance scores above 6.5. Based on the results, replacement up to 100% of chicken skin with GBB is possible and obtains a healthier emulsified meat product with good sensory acceptance.

Role of milk and honey in the tolerance of lactobacilli to oxidative stress.

In the development of functional probiotic food, the carrier matrices should be carefully selected and optimized to ensure the highest levels of probiotic survival in the symbiotic food along storage. Because milk and honey food matrices are rich in antioxidant substances, the aim of the research was to evaluate their effect in protecting lactobacilli from reactive oxygen species (ROS) generated by the addition of hydrogen peroxide. Viability assays were performed with and without the addition of H2O2, in three different matrices: 0.9% peptone saline, 5% honey, or 12% reconstituted skim milk. The milk matrix provided protection for the Lacticaseibacillus paracasei DTA83 and Lacticaseibacillus rhamnosus DTA76. However, this protective effect was not observed in the survival of Lactobacillus acidophilus La 5. Honey solution did not maintain the viability of probiotic microorganisms exposed to hydrogen peroxide and, on the contrary, caused a significant reduction in the population of L. rhamnosus DTA76 (p < 0.001). Lower membrane lipid peroxidation due to H2O2 exposure was observed in L. acidophilus La 5 and L. rhamnosus DTA76, but this marker showed no relation with viability. It was concluded: (i) lactobacilli from the Lacticaseibacillus genus were the ones that benefited most from the lactic environment; (ii) the absence of the protective effect of honey was possibly due to the presence of Fe2+ which reacts with H2O2 to produce hydroxyl radicals; and (iii) cell viability did not correlate with membrane lipid peroxidation, and it is not a good marker to evaluate this type of damage in cells of different microorganisms.

Craft Beers Fermented by Potential Probiotic Yeast or Lacticaseibacilli Strains Promote Antidepressant-Like Behavior in Swiss Webster Mice.

This study aimed to produce a probiotic-containing functional wheat beer (PWB) by an axenic culture system with potential probiotic Saccharomyces cerevisiae var boulardii 17 and probiotic-containing functional sour beer (PSB) by a semi-separated co-cultivation system with potential probiotic Lacticaseibacillus paracasei DTA 81 and Saccharomyces cerevisiae S-04. Additionally, results obtained from in vivo behavioral tests with Swiss Webster mice treated with PWB or PSB were provided, which is scarce in the current literature. Although the use of S. boulardii to produce beers is not a novelty, this study demonstrated that S. boulardii 17 performance on sugar wort stills not completely elucidated; therefore, further studies should be considered before using the strain in industrial-scale production. Co-culture systems with lacticaseibacilli strain and S. cerevisiae have been reported in the literature for PSB production. However, lacticaseibacilli survivability in beer can be improved by semi-separated co-cultivation systems, highlighting the importance of growing lacticaseibacilli in the wort before yeast pitching. Besides, kettle hopping must be chosen as the method for hop addition to produce PSB. The dry-hopping method may prevent iso-alpha formation in the wort; however, a tendency to sediment can drag cells at the tank bottom and negatively affect L. paracasei DTA 81 viability. Despite stress factors from the matrices and the stressful conditions encountered during GI transit, potential probiotic S. boulardii 17 and potential probiotic L. paracasei DTA 81 withstood at sufficient doses to promote antidepressant effects in the mice group treated with PWB or PSB, respectively.

Potentially probiotic or postbiotic pre-converted nitrite from celery produced by an axenic culture system with probiotic lacticaseibacilli strain.

The present study evaluated the use of the probiotic Lacticaseibacillus paracasei DTA-83 as a nitrite-reducing agent to produce potentially probiotic or postbiotic pre-converted nitrite from celery. The results obtained were compared to those achieved by direct addition of sodium nitrite for the typical reddish color formation in cooked pork sausages and the inhibitory potential against the growth of target microorganisms, including the clostridia group. Regarding the sausages color, similar findings were observed when comparing the use of pre-converted nitrite from celery produced by L. paracasei DTA-83 and the direct addition of sodium nitrite. Additionally, it presented an inhibitory effect against Salmonella spp., which was not observed with the direct addition of nitrite, revealing a potential strategy to control salmonellosis in the matrix. However, a non-equivalent preservative effect against Clostridium perfringens (INCQS 215) was determined. The results highlight a promising alternative to produce probiotic or postbiotic meat ingredients; however, further studies should be conducted to investigate doses that achieve microbial control.

Safety and Stability of Two Potentially Probiotic Lactobacillus Strains After In Vitro Gastrointestinal Transit.

According to FAO and WHO, probiotics are defined as live microorganisms that, when administered in adequate amounts, confer a health benefit on the host. Most probiotic bacteria used today belong to the genera Lactobacillus and Bifidobacterium and are of animal or human origin. The fundamental characteristic routinely evaluated in potential probiotics strains is their limited viability loss during gastrointestinal transit (GIT), but to date, no studies reported whether probiotics, besides viability, still also maintain their beneficial properties intact. To study this aspect, we considered two strains, Lactobacillus rhamnosus DTA 79 and L. paracasei DTA 83, previously characterised for the presence of some probiotic properties, isolated from faeces of 7- to 21-day-old babies. Here, we examined some additional properties, namely antibiotic resistance, resistance to lysozyme, presence of haemolytic activity and inhibition of pathogen biofilm formation. We then tested the effect of in vitro GIT on all these features and our results show evidence that this procedure had in some cases limited and in others no significant effects on them. Additionally, we examined the gastrointestinal resistance of the strains after skim milk fermentation and successive storage of the product for 20 and 40 days at refrigeration temperature, to see whether prolonged storage could weaken cell resistance to GIT. Our results demonstrate that a protracted refrigeration period before in vitro GIT did not affect or influenced very weakly this essential probiotic property.

Physically Cross-Linked Gels of PVA with Natural Polymers as Matrices for Manuka Honey Release in Wound-Care Applications.

Manuka honey is a well-known natural material from New Zealand, considered to have properties beneficial for burn treatment. Gels created from polyvinyl alcohol (PVA) blended with natural polymers are potential burn-care dressings, combining biocompatibility with high fluid uptake. Controlled release of manuka honey from such materials is a possible strategy for improving burn healing. This work aimed to produce polyvinyl alcohol (PVA), PVA⁻sodium carboxymethylcellulose (PVA-CMC), PVA⁻gelatin (PVA-G), and PVA⁻starch (PVA-S) cryogels infused with honey and to characterize these materials physicochemically, morphologically, and thermally, followed by in vitro analysis of swelling capacity, degradation/weight loss, honey delivery kinetics, and possible activity against Staphylococcus aureus. The addition of honey to PVA led to many PVA crystals with defects, while PVA⁻starch⁻honey and PVA⁻sodium carboxymethylcellulose⁻honey (PVA-CMC-H) formed amorphous gels. PVA-CMC presented the highest swelling degree of all. PVA-CMC-H and PVA⁻gelatin⁻honey presented the highest swelling capacities of the honey-laden samples. Weight loss/degradation was significantly higher for samples containing honey. Layers submitted to more freeze⁻thawing cycles were less porous in SEM images. With the honey concentration used, samples did not inhibit S. aureus, but pure manuka honey was bactericidal and dilutions superior to 25% honey were bacteriostatic, indicating the need for higher concentrations to be more effective.

Draft genome sequence data of Lactobacillus paracasei strain DTA83 isolated from infant stools.

Here the draft genome sequence of Lactobacillus paracasei strain DTA83, isolated from stools of healthy infants in Rio de Janeiro (Brazil), is reported. The 2.8-Mb genome possesses 2825 protein-coding sequences distributed on 330 SEED subsystems. This strain belongs to a set of potentially probiotic Lactobacillus spp. strains used to study genetic factors related to antibiotic resistance after stress conditions, such as simulated gastrointestinal conditions. The complete genome data have been deposited in GenBank under the accession number QRBH00000000, https://www.ncbi.nlm.nih.gov/nuccore/QRBH00000000.

Hot topic: Holder pasteurization of human milk affects some bioactive proteins.

The aim of this research was to investigate the effect of Holder pasteurization (HoP; 62.5°C, 30 min) on the protein profile and activities of glutathione peroxidase (GPx) and lysozyme (LZ) in human milk. Over 6 mo of lactation, human milk samples were analyzed before (raw) and after HoP for GPx and LZ activity and electrophoresis protein profile. Holder pasteurization reduced human milk lactoferrin, immunoglobulin fractions, and GPx activity. In addition, GPx activity, which is high in colostrum and transitional milk, was naturally reduced over the 6-mo lactation period. In contrast, HoP did not affect human milk LZ activity. Besides its critical cellular antioxidant role in protecting the organism from oxidative damage, GPx decreases the redox potential of milk, stimulating the growth of anaerobic microorganisms, such as the probiotic Bifidobacterium. Considering the role of lactoferrin in infant health, we conclude that an important part of its function has been inactivated by pasteurization. These compounds should be replaced by human milk banks after the HoP step to recover lost functionality. Otherwise, an alternative technology to HoP that better retains human milk properties should be used by milk banks to eliminate the risk of transmission of infectious agents.

Lactobacillus paracasei probiotic properties and survivability under stress-induced by processing and storage of ice cream bar or ice-lolly / Propriedades probióticas e sobrevivência de Lactobacillus paracasei sobre estresse induzido pelo processamento e armazenamento em picolé a base de leite ou água

ABSTRACT: Probiotics are live microorganisms which, when administered in adequate amounts, confer a health benefit on the host. The aim of this study was to identify genotypically lactobacilli strains isolated from newborn stools and selecting strain based on probiotic properties (gastrointestinal tolerance, antibiotic susceptibility, inhibition of pathogen biofilm formation, absence of alfa or gamma-blood hemolysis, and lysozyme sensibility) and technological properties of surviving either in ice cream bar or ice-lolly. Reduction of 1.2log cfu ml-1 of the Lactobacillus paracasei strain was observed after exposure through in vitro gastrointestinal conditions. It inhibited biofilms of Escherichia coli, Salmonella Typhimurium and Candida albicans by mechanisms of competition, exclusion and displacement, and was resistant up to 3000μg ml-1 of egg white lysozyme. It presented neither alfa nor gamma-hemolysis or was antibiotic resistant to usual antibiotics for human use. Microbial survivability in ice cream bar or ice-lolly was assessed up to 21 days of storage at -18°C. Viability was maintained in ice cream bar, but there was a reduction of almost 2.0logs in ice-lolly.

RESUMO: Probióticos são microrganismos vivos que, quando administrados em quantidade adequadas, conferem benefícios à saúde do hospedeiro. O objetivo desta pesquisa foi identificar genotipicamente lactobacilos isolados de material fecal de recém-nascidos, assim como selecionar uma cepa com base em suas propriedades probióticas (tolerância às condições gastrointestinais, susceptibilidade à antibióticos, inibição da formação de biofilmes por microrganismos patogênicos, ausência de hemólise alfa ou gama e sensibilidade à lisozima) e tecnológicas de sobrevivência em picolé à base de água ou leite. Houve redução de 1,2log ufc ml-1 do isolado identificado como Lactobacillus paracasei após passagem pelas condições gastrointestinais in vitro. Esta cepa inibiu a formação de biofilmes de Escherichia coli, Salmonella Typhimurium e Candida albicans pelos mecanismos de competição, exclusão e desacoplamento e apresentou resistência até 3000μg ml-1 frente a lisozima de ovo. Entre os aspectos de segurança, a cepa não apresentou hemólise alfa ou gama e não foi resistente a antibióticos comumente ministrados em humanos. A sobrevivência microbiana em picolé a base de água ou leite foi analisada ao longo de 21 dias de estocagem a -18°C. Houve manutenção da viabilidade no produto à base de leite, mas naquele à base de água, ocorreu redução de quase 2,0logs.

A importância do uso das ferramentas de controle de qualidade para o setor de açougue / The importance of using quality control tools for the butcher industry

A carne é um alimento muito consumido pela população e possui elevado valor nutritivo. O Brasil se destaca como grande exportador de bovinos, aves e suínos e o consumo per capita vêm aumentando anualmente. Este aumento no consumo gera uma preocupação quanto à segurança microbiológica deste alimento, pois a carne possui características intrínsecas que propiciam o crescimento microbiano e por este motivo alguns cuidados precisam ser tomados na manipulação. Os locais onde as carnes normalmente são manipuladas, armazenadas e comercializadas são os açougues e estes estabelecimentos precisam adotar medidas para evitar a contaminação das mesmas por micro-organismos indesejáveis. Estas medidas podem ser aplicadas com o auxílio de ferramentas de qualidade que podem apontar os pontos de maiores riscos de contaminação microbiana. Este estudo teve como objetivo apresentar algumas ferramentas de controle de qualidade que podem ser aplicadas no setor açougue. Com a utilização destas ferramentas é possível identificar os problemas, ou seja, as não conformidades e, com a correta análise, buscar a melhor solução.

Meat is a food widely consumed by the population and it has a high nutritious value. Brazil stands out as a major exporter of cattle, poultry and pigs, and the per capita consumption has been increasing annually. The increase of consumption is a concern regarding microbiological safety of this food, because the meat has characteristics in favor of microbial growth. For this reason some caremust be taken while handling the product. The places where the meat are usually handled, stored and sold are the butchers, and these facilities need measures to avoid undesirable microorganisms contamination. These procedures can be implemented with quality tools, pointing the highest microbial contamination risk. This study aims to present some quality control tools that can be applied to the butcher sector. Using these tools is possible to identify problems and seek the best solutions.

Psychrotrophic bacteria in milk: How much do we really know?

The occurrence of psychrotrophic bacteria in raw milk is studied worldwide due to the difficulties associated with controlling their growth during cold storage and the consequent negative effects upon fluid milk or dairy products. Among the psychrotrophic bacteria, the genus Pseudomonas (represented primarily by P. fluorescens) has been highlighted as the cause of numerous defects in dairy products. In light of its perceived predominance, this species has frequently been chosen as a model organism to assess the effects of psychrotrophic bacteria on milk or to evaluate the efficacy of control measures. However, recent findings derived from the application of molecular biological techniques have exposed a number of deficiencies in our knowledge of the biology of milk-associated psychrotrophs. Furthermore, it has been revealed that microbe to microbe communication plays a significant role in determining both the identities and the extent to which different groups of microbes develop during cold storage. The application of molecular identification methods has exposed errors in the classification of members of the genus Pseudomonas isolated from cold stored milk and has stimulated a reevaluation of the presumed status of P. fluorescens as the predominant milk-associated psychrotrophic species. This article presents a succinct review of data from studies on psychrotrophic bacteria in milk, some of which contest established theories in relation to the microbiology of cold stored raw milk, and poses the question: how much do we really know?

Psychrotrophic bacteria in milk: How much do we really know?

The occurrence of psychrotrophic bacteria in raw milk is studied worldwide due to the difficulties associated with controlling their growth during cold storage and the consequent negative effects upon fluid milk or dairy products. Among the psychrotrophic bacteria, the genus Pseudomonas (represented primarily by P. fluorescens) has been highlighted as the cause of numerous defects in dairy products. In light of its perceived predominance, this species has frequently been chosen as a model organism to assess the effects of psychrotrophic bacteria on milk or to evaluate the efficacy of control measures. However, recent findings derived from the application of molecular biological techniques have exposed a number of deficiencies in our knowledge of the biology of milk-associated psychrotrophs. Furthermore, it has been revealed that microbe to microbe communication plays a significant role in determining both the identities and the extent to which different groups of microbes develop during cold storage. The application of molecular identification methods has exposed errors in the classification of members of the genus Pseudomonas isolated from cold stored milk and has stimulated a reevaluation of the presumed status of P. fluorescens as the predominant milk-associated psychrotrophic species. This article presents a succinct review of data from studies on psychrotrophic bacteria in milk, some of which contest established theories in relation to the microbiology of cold stored raw milk, and poses the question: how much do we really know?.

Survival of free and microencapsulated Bifidobacterium: effect of honey addition.

This study evaluated the effect of honey addition on the viability of free and emulsion encapsulated cells of two strains of Bifidobacterium that underwent simulation of human upper gastrointestinal transit. In the control condition, without honey, free cells were drastically reduced after exposure to gastrointestinal conditions. The reduction was more pronounced with Bifidobacterium J7 of human origin. On the other hand, when cells were encapsulated, the viability reduction was higher for strain Bifidobacterium Bb12. The microencapsulation improved the viability maintenance of both Bifidobacterium strains, in recommended amounts for probiotic activity, after exposure to simulated gastrointestinal conditions. Moreover, suspending free cells of both Bifidobacterium strains in honey solutions resulted in a protective effect, equivalent to the plain microencapsulation with sodium alginate 3%. It is concluded that microencapsulation and the addition of honey improved the ability of Bifidobacterium to tolerate gastrointestinal conditions in vitro.

Contaminação fúngica no leite humano e em sítios anatômicos de lactantes e lactentes / Fungal contamination in human milk and in the anatomic sites of breastfeeding mothers and infants

As infecções bacterianas ou fúngicas causam quadro clínico de mastite, que motiva desmame precoce. Os micro-organismos patogênicos, como leveduras do gênero Candida, quando em número elevado no intestino, podem causar disbiose. Nesta pesquisa, foram realizadas a detecção e a identificação de microbiota fúngica nas amostras de leite humano e de sítios anatômicos de mulheres e crianças atendidas pelo Banco de Leite Humano do Instituto Fernandes Figueira. A virulência dos isolados de levedura foi determinada pelos testes de atividade proteolítica. De 64 amostras analisadas, 81% foram positivas para fungos, com maior prevalência de Candida albicans (73%), seguida do complexo C. parapsilosis (15,4%). Perfis semelhantes aos verificados no total de amostras foram encontrados nas amostras de leite, nas mamas e na cavidade oral, sugerindo-se a ocorrência de associação entre a infecção cutânea da mãe e do lactente com o leite ingerido. O perfil associado à virulência dos isolados de Candida foi determinado pelo teste de produção de proteases, e 100% das amostras mostraram resultados fortemente positivos, indicando alto grau de infecciosidade. A alta prevalência de C. albicans nas amostras coletadas de mamas, no leite e na cavidade oral, é importante fator de risco à saúde de lactentes.

Campylobacter spp em carne de ave crua: avaliação da etapa de resfriamento / Campylobacter spp in fresh meat poultry: chilling step assessment

Na obtenção de carcaças, cortes ou carnes desossadas de aves com qualidade assegurada, várias etapas indispensáveis devem ser seguidas de maneira eficiente, desde a granja avícola até a fase do consumo. As carnes de aves são consideradas alimentos que apresentam elevado risco de transmissão de doenças, como a campilobacteriose. Neste estudo, foi analisado o papel da etapa de resfriamento das carcaças na contaminação com Campylobacter spp. Para tanto, foram coletadas amostras das carcaças com swabs, após o resfriamento do produto, bem como a amostra da água usada nos tanques para tal finalidade. Das amostras de carcaças analisadas, 27% apresentaram resultados positivos para Campylobacter spp. Houve predominância de Campylobacter jejuni biotipo I nos isolados identificados e biotipificados, entretanto, essa bactéria não foi detectada na água de resfriamento. Considera-se que o controle da contaminação com essas bactérias deve ser feito ainda no plantel, na ave viva. Visto que a bactéria é sensível ao cozimento, recomenda-se consumir esse alimento bem cozido, tomando-se os devidos cuidados durante o preparo, para que não ocorra contaminação cruzada com alimentos que são ingeridos crus.

In order to achieve the assured quality in carcasses, cuts or boneless poultry meat, some fundamentalprocedures must be followed throughout the poultry chain, from the farm to consumers. Poultry productsare considered as foods with high risk for diseases transmission such as campilobacteriosis. As the chickenmeat is highly consumed by Brazilian people, this study was conducted to analyze the role of the chilling stagein the poultry processing in inducing the contamination with Campylobacter spp. For this purpose, samplesfrom the carcasses were swabbed after chilling, and also the chilling water was analyzed. Campylobacter spppositive results were shown in 27% of the analyzed carcasses. The isolates were identified and biotypified, andthe predominance of Campylobacter jejuni biotype I was showed; however, Campylobacter was not isolatedfrom chilling water sample. Considering that neither the chilling in chlorinated water nor any other stepin the poultry processing do eliminate and/or inactivate the bacterium, the bacteria contamination controlshould start just at the breeding stage, in the alive bird. Since the bacterium is heat sensible, it is advisableto consume well-cooked poultry, and to avoid cross contamination with raw foods.

Effect of three different types of culture conditions on Spirulina maxima growth

Growth of Spirulina maxima was studied in three types of culture conditions with four replicates each: 1) manual aeration with natural sunlight; 2) manual aeration with artificial light; and 3) constant aeration with an aquarium compressor and artificial light. After 185 days of incubation, growth declined in the first two treatments, while in the third treatment, higher growth was observed with average optical density of 3.7 against 1.8 and 1.9 in the first and second treatment, respectively. This was probably due to the fact that under constant aeration the salts were suspended avoiding the crystallization what could cause a decrease in the availability of the necessary nutrients for the growth. Also, the constant stirring allowed all the cells to receive the same amount of light promoting photosynthesis and consequently, a larger growth and characteristic green coloration. Culture with constant aeration under artificial light should be used for S. maxima cultivation because, besides reducing labor hours, it could be a more effective method for improving the economic income.

O crescimento de Spirulina máxima foi estudado em três condições de cultivo: 1) agitação manual com iluminação natural; 2) agitação manual com iluminação artificial e; 3) agitação constante feita por compressor de aquário e iluminação artificial. O maior crescimento foi observado nesta última condição, onde após 185 dias foram observados valores médios de densidade ótica de 3,7 enquanto, valores de 1,8 e 1,9 foram obtidos no primeiro e segundo experimento, respectivamente. Diferentemente do ocorrido com os outros tratamentos, não foi observado declínio no crescimento após 185 dias, o que foi atribuído ao fato de que, sob constante agitação os sais ficam suspensos e não cristalizam, fato que acarretaria diminuição da disponibilidade de nutrientes necessários ao crescimento. Também a agitação constante permite que todas as células recebam a mesma iluminação, promovendo fotossíntese e consequentemente um maior crescimento e coloração verde característica. Conclui-se que o emprego do compressor de aquário é não somente viável, mas recomendável, pois além de diminuir a mão de obra ainda se mostrou mais eficaz, melhorando o rendimento.

Inhibitory effect of acetic acid on bioconversion of xylose in xylitol by Candida guilliermondii in sugarcane bagasse hydrolysate

Hidrolisado de bagaço de cana-de-açúcar contendo uma concentração inicial de ácido acético de 3,5g/L foi utilizado como meio de fermentação para a bioconversão de xilose em xilitol pela levedura Candida guilliermondii FTI 20037. Ácido acético (2,0g/L) foi adicionado ao meio em diferentes tempos de fermentação, com o objetivo de avaliar o efeito deste ácido neste bioprocesso. O maior efeito inibitório deste ácido na bioconversão de xilose em xilitol pela levedura ocorreu quando este foi adicionado ao meio após 12h de fermentação. Nesta condição observou-se uma redução de 23,22 porcento e 11,24 porcento, respectivamente, no consumo de xilose e no crescimento celular em relação à fermentação em que a adição deste ácido ocorreu no tempo inicial de incubação. Como conseqüência do efeito inibitório, observou-se os menores valores de rendimento (0,39g/g) e produtividade (0,22g/L.h) de xilitol, correspondendo a uma redução de 36 e 48 porcento, respectivamente, em relação aos valores obtidos com a adição de ácido acético nos outros tempos de fermentação. Os resultados obtidos permitem concluir que, nas condições experimentais empregadas neste trabalho, o efeito inibitório do ácido acético sobre a bioconversão de xilose em xilitol é dependente do tempo de fermentação em que a adição do ácido foi feita e não apenas de sua concentração no meio.

Identificação dos pontos críticos de controle na preparação de carne bovina assada, em unidades de alimentação e nutrição / Identification of the control critics points in the preparation of meat cattle, in units of food and nutrition

Os alimentos nas diferentes etapas de sua produção, até o consumo, necessitam de avaliação completa de seus riscos, que é estabelecida através de normas aceitáveis de boas práticas de fabricação. Os produtos de origem animal apresentam qualidade nutricional superior aos produtos vegetais, porém podem tornar-se veículos de organismos potencialmente nocivos ao homem, quando mantidos em condições inadequadas de conservação e distribuição, necessitando assim de rigorosa inspeção sanitária. Neste contexto, a carne bovina é um alimento nutricionalmente importante para a manutenção da saúde, e a carne bovina assada é um tipo de preparação amplamente utilizada em unidades de alimentação e nutrição, sendo necessário, portanto, utilizar-se de adequadas normas higiênicas e controle total de qualidade durante as etapas de preparação. A identificação dos PCC envolvidos nas diferentes etapas de preparação da carne bovina assada em U.A.N permite o conhecimento dos principais perigos, medidas de controle e monitoramento, contribuindo assim para a obtenção de um produto final com maior preservação de sua qualidade nutricional, melhores características sensoriais e maior segurança para o consumidor.

Ochratoxin A on green coffee: influence of harvest and drying processing procedures.

Ochratoxin A is a metabolite produced by Aspergillus and Penicillium species that is nephrotoxic and possibly carcinogenic to humans. The aim of this study was to evaluate ochratoxin A contamination in green coffee obtained by different harvesting and drying operations and from fruits of different ripening stages in order to identify hazards. The research was directed to coffees from the highland area of Rio de Janeiro state (Brazil), which is traded in the domestic market. Twenty-two out of 54 samples contained ochratoxin A at levels ranging from 0.3 to 160 microg/kg. Ochatoxin A contamination levels between different ripe stage fruits were not significant (P > 0.05). "Varrição" coffee, consisting of fruits that fell from the tree spontaneously and stayed longer on the ground before being harvested, was the most contaminated. Eleven out of 14 samples of varrição coffee were contaminated. Three out of 10 samples from the northwestern region of the state were positive for ochratoxin at levels ranging from 10.1 to 592 microg/kg. The contaminated samples had in common the fact that they were harvested directly from the soil.