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.

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.

From the vineyard to the cellar: new insights of Starmerella bacillaris (synonym Candida zemplinina) technological properties and genomic perspective.

A large diversity of yeasts can be involved in alcoholic fermentation; however, Starmerella bacillaris strains have gained great attention due to their relevant and particular characteristics. S. bacillaris is commonly known as an osmotolerant, acidogenic, psychrotolerant, and fructophilic yeast. Most strains of this species are high producers of glycerol and show low ethanol production rates, being highlighted as promising alternatives to the manufacture of low-alcohol beverages. The increased production of high alcohols, such as benzyl alcohol that has antifungal and antibacterial properties, highlights S. bacillaris potential as a biocontrol agent. After harvest, antifungal yeasts become part of the must microbiota and may also improve the fermentation process. Moreover, during the fermentation, S. bacillaris releases important molecules with biotechnological properties, such as mannoproteins and glutathione. Considering the potential biotechnological properties of S. bacillaris strains, this review presents an overview of recent trends concerning the application of S. bacillaris in fermented beverages. KEY POINTS: •S. bacillaris as an alternative to the production of low-alcohol beverages. •S. bacillaris strains present biocontrol potential. •Molecules released by S. bacillaris may be of great biotechnological interest.

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.

Complete Genome Sequence and Carbohydrates-Active EnZymes (CAZymes) Analysis of Lactobacillus paracasei DTA72, a Potential Probiotic Strain with Strong Capability to Use Inulin.

The whole genome sequence of Lactobacillus paracasei DTA72, isolated from healthy infant feces, is reported, along with the Carbohydrates-Active enZymes (CAZymes) analysis and an in silico safety assessment. Strain DTA72 had previously demonstrated some interesting potential probiotic features, such as a good resistance to gastrointestinal conditions and an anti-Listeria activity. The 3.1 Mb sequenced genome consists of 3116 protein-coding sequences distributed on 340 SEED subsystems. In the present study, we analyzed the fermentation capability of strain DTA72 on six different carbohydrate sources, namely, glucose, fructose, lactose, galactose, xylose, and inulin by using phenotypical and genomic approaches. Interestingly, L. paracasei DTA72 evidenced the best growth performances on inulin with a much shorter lag phase and higher number of cells at the stationary phase in comparison with all the sugars tested. The CAZyme analysis using the predicted amino acid sequences detected 80 enzymes, distributed into the five CAZymes classes. Moreover, the in silico analysis revealed the absence of blood hemolytic genes, transmissible antibiotic resistances, and plasmids in DTA72. The results described in this study, together with those previously reported and particularly the strong capability to utilize inulin as energy source, make DTA72 a very interesting potential probiotic strain to be considered for the production of synbiotic foods. The complete genome data have been deposited in GenBank under the accession number WUJH00000000.

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.

Growth Parameters and Survivability of Saccharomyces boulardii for Probiotic Alcoholic Beverages Development.

The aim of this research was to optimize the growth parameters (pH, ethanol tolerance, initial cell concentration and temperature) for Saccharomyces boulardii and its tolerance to in vitro gastrointestinal conditions for probiotic alcoholic beverage development. Placket-Burman screening was used to select only statistically significant variables, and the polynomial mathematical model for yeast growth was obtained by central composite rotatable design. Confirmation experiments to determine the kinetic parameters for yeast growth were carried out by controlling the temperature and pH. Soon after, the survivability of yeast was tested under in vitro conditions mimicking the human upper gastrointestinal transit. S. boulardii had suitable resistance to alcohol and gastrointestinal conditions for probiotic alcoholic beverage development.

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.

Qualidade microbiológica da água consumida pela população do distrito de Sana, Macaé, Rio de Janeiro / Microbiological quality of water consumed by population of the district Sana, Macaé, Rio de Janeiro

A qualidade da água consumida pela população distrito de Sana, Macaé,RJ foi avaliada por meio de análises microbiológicas para pesquisa de coliformes termotolerantes e totais e bactérias heterotróficas baseando-se na portaria nº518/2004- Ministério da Saúde. A água consumida...