Viability of a Five-Strain Mixture of Listeria monocytogenes in Vacuum-Sealed Packages of Frankfurters, Commercially Prepared with and without 2.0 or 3.0% Added Potassium Lactate, during Extended Storage at 4 and 10° C†‡

The viability of Listeria monocytogenes was monitored on frankfurters containing added potassium lactate that were obtained directly from a commercial manufacturer. Eight links (ca. 56 g each) were transferred aseptically from the original vacuum-sealed bulk packages into nylon-polyethylene bags. Each bag then received a 4-ml portion of a five-strain mixture of the pathogen. Frankfurters containing 2.0 or 3.0% potassium lactate were evaluated using 20 CFU per package, and frankfurters containing 3.0% potassium lactate were evaluated using 500 CFU per package. The packages were vacuum-sealed and stored at 4 or 10°C for up to 90 or 60 days, respectively. During storage at 4°C, pathogen numbers remained at about 1.6 log10 CFU per package over 90 days in packages containing frankfurters with 2.0% potassium lactate that were inoculated with about 20 CFU. In packages containing frankfurters with 3.0% potassium lactate that were inoculated with about 20 CFU and stored at 4°C, pathogen numbers remained at about 1..

DETECÇÃO DE BACTERIOCINAS PRODUZIDAS POR Lactobacillus plantarum BN EM MELAÇO DE CANA-DE-AÇÚCAR SOB FERMENTAÇÃO SUBMERSA

Verificou-se a presença de bacteriocinas produzidas por Lactobacillus plantarum BN (microrganismo teste) em caldo com 3% de melaço de cana-de-açúcar, centrifugado e enriquecido com extrato de leveduras, acetato de sódio e citrato de amônia. Os testes foram realizados em fermentador com volume de trabalho de 3,0 L, sob agitação contínua a 100 rpm, temperatura de 30 ± 0,1°C, aeração de 0,7 vvm, tempo de fermentação de 24 horas e inóculo aproximado de 6,0 Log10 UFC/mL, com tomada de amostras em intervalos de 2 horas. O maior número médio de células viáveis foi de 10 Log10 ciclos logarítmicos, nos intervalos de 12 a 18 horas de fermentação. O pH inicial de 6,49, após 24 horas diminuiu para 5,05. A detecção de bacteriocinas foi realizada no sobrenadante obtido por centrifugação do meio de cultivo, pelo método de difusão em orifícios, usando Lactobacillus sakei ATCC 15521 como microrganismo indicador. Verificouse a presença de bacteriocinas no meio de cultivo a partir de 8 horas de fermentação pela formação de halo inibitório, quando o microrganismo encontrava-se na fase exponencial de crescimento. Comprovou-se a natureza protéica da bacteriocina pelo uso da enzima a-quimotripsina. A bacteriocina produzida por L. plantarum BN apresentou efeito inibitório sobre Listeria monocytogenes ATCC 19112, mas não sobre Staphylococcus aureus ATCC 15489. DETECTION OF BACTERIOCIN PRODUCED BY Lactobacillus plantarum BN IN SUGAR-CANE MOLASSES BY SUBMERSE FERMENTATION Abstract The presence of bacteriocins produced by Lactobacillus plantarum BN (test microorganism) in 3% sugar cane molasses, centrifuged and enriched with yeast extract, sodium acetate and ammonium citrate, was verified. The tests were realized in a fermenter with 3.0 L work volume, under continuous agitation of 100 rpm, at a temperature of 30 ± 0.1 °C, 0.7 vvm aeration and fermentation time of 24 hours with an approximate inoculum of 6.0 Log10 CFU/mL with sample being taken at every 2 hours interval. The greatest number of viable cells observed was 10 Log10 logarithmic cycles at 12 and 18 hours fermentation intervals. Initial pH was 6,49 and after 24 hours, it decreased to 5,05. Bacteriocins detection was accomplished using the supernatant obtained by centrifugation of cultivation media in the well diffusion method using Lactobacillus sakei ATCC 15521 as the indicator microorganism. From 8 hours on of fermentation, presence of colonies surrounded by a clear zone of inhibition indicated bacteriocins production in cultivation media when the microorganism was in the exponential growth phase. The proteic nature of the bacteriocin was certified by using the a-chimotrypsin enzyme. The bacteriocin produced by Lactobacillus plantarum BN presented inhibiting effect over Listeria monocytogenes ATCC 19112 while this effect was not observed in Staphylococcus aureus ATCC 15489

Fate of Listeria monocytogenes and Shiga Toxin-Producing Escherichia coli on Bresaola Slices During Storage

The viability of multistrain cocktails of genetically marked strains of Listeria monocytogenes and Shiga toxin-producing Escherichia coli (STEC) were separately monitored on slices of one brand of a commercially produced bresaola (ca. pH 6.7 and aw 0.899) during extended storage at refrigeration and abusive temperatures. Two slices (ca. 8 g each; ca.10.2 cm wide, ca. 11 cm long) of bresaola were layered horizontally within a nylon-polyethylene bag. The outer surface of each slice was inoculated (50μL total; ca. 3.5 log colony-forming units [CFU]/package) with a rifampicin-resistant (100μg/mL) cocktail of either L. monocytogenes (5 strains) or STEC (8 strains). Bags were vacuum-sealed and then stored at 4°C or 10°C for 180 or 90 d, respectively. In each of 5 trials, 3 bags were analyzed for pathogen presence at each sampling interval via the US Department of Agriculture–Agricultural Research Service package rinse method. In general, levels of L. monocytogenes and STEC decreased by 3.0 and 2.4 log CFU/package, respectively, after 180 d when bresaola was stored at 4°C. When bresaola was stored at 10°C for 90 d, levels of L. monocytogenes and STEC decreased by 2.4 and 3.1 log CFU/package, respectively. Thus, the sliced bresaola evaluated herein did not provide a favorable environment for either persistence or outgrowth of surface-inoculated cells of L. monocytogenes or STEC

Light fragments production and isospin dependences in Sn+Ni and Sn+Al central collisions at 25MeV/A and 35MeV/A from reverse/isospin experiments

This paper presents the physical analysis results for the following reactions: 124Sn+64Ni, 124Sn+27Al, 124Sn+58Ni at 35MeV/A and 25MeV/A. The main goal of this studies was to find observables sensitive to isospin effects and to present the similarities/differences between the systems characterised by various charge asymmetry factor, defined as I = (NZ)=A. Theoretical simulations based on the Quantum Molecular Dynamics (QMD) model have been performed in order to compare them with the results of the analysis of experimental data. The first phase of the reaction was carried out with the code CHIMERA [1]. The sequential decay of hot fragments was simulated by the code COOLER [2]. The conclusions are as follows: there are observables sensitive to the isospin of the system, such as the Light Charged Particles (LCP) emission and their sensitivity is demonstrated more prominently in the analysis of central collisions at 35MeV/A. The theoretical calculations do not reproduce these relations well

Measuring collective action intention toward gender equality across cultures

Collective action is a powerful tool for social change and is fundamental to women and girls’ empowerment on a societal level. Collective action towards gender equality could be understood as intentional and conscious civic behaviors focused on social transformation, questioning power relations, and promoting gender equality through collective efforts. Various instruments to measure collective action intentions have been developed, but to our knowledge none of the published measures were subject to invariance testing. We introduce the gender equality collective action intention (GECAI) scale and examine its psychometric isomorphism and measurement invariance, using data from 60 countries (N = 31,686). Our findings indicate that partial scalar measurement invariance of the GECAI scale permits conditional comparisons of latent mean GECAI scores across countries. Moreover, this metric psychometric isomorphism of the GECAI means we can interpret scores at the country-level (i.e., as a group attribute) conceptually similar to individual attributes. Therefore, our findings add to the growing body of literature on gender based collective action by introducing a methodologically sound tool to measure collective action intentions towards gender equality across cultures.info:eu-repo/semantics/acceptedVersio

Chromosome evolution in fishes: a new challenging proposal from Neotropical species

We present a database containing cytogenetic data of Neotropical actinopterygian fishes from Venezuela obtained in a single laboratory for the first time. The results of this study include 103 species belonging to 74 genera assigned to 45 families and 17 out of the 40 teleost orders. In the group of marine fishes, the modal diploid number was 2n=48 represented in 60% of the studied species, while in the freshwater fish group the modal diploid complement was 2n=54, represented in 21.21 % of the studied species. The average number of chromosomes and the mean FN were statistically higher in freshwater fish than in marine fish. The degree of diversification and karyotype variation was also higher in freshwater fish in contrast to a more conserved cytogenetic pattern in marine fish. In contrast to the assumption according to which 48 acrocentric chromosomes was basal chromosome number in fish, data here presented show that there is an obvious trend towards the reduction of the diploid number of chromosomes from values near 2n=60 with high number of biarmed chromosomes in more basal species to 2n=48 acrocentric elements in more derived Actinopterygi

Catálogo Taxonômico da Fauna do Brasil: setting the baseline knowledge on the animal diversity in Brazil

The limited temporal completeness and taxonomic accuracy of species lists, made available in a traditional manner in scientific publications, has always represented a problem. These lists are invariably limited to a few taxonomic groups and do not represent up-to-date knowledge of all species and classifications. In this context, the Brazilian megadiverse fauna is no exception, and the Catálogo Taxonômico da Fauna do Brasil (CTFB) (http://fauna.jbrj.gov.br/), made public in 2015, represents a database on biodiversity anchored on a list of valid and expertly recognized scientific names of animals in Brazil. The CTFB is updated in near real time by a team of more than 800 specialists. By January 1, 2024, the CTFB compiled 133,691 nominal species, with 125,138 that were considered valid. Most of the valid species were arthropods (82.3%, with more than 102,000 species) and chordates (7.69%, with over 11,000 species). These taxa were followed by a cluster composed of Mollusca (3,567 species), Platyhelminthes (2,292 species), Annelida (1,833 species), and Nematoda (1,447 species). All remaining groups had less than 1,000 species reported in Brazil, with Cnidaria (831 species), Porifera (628 species), Rotifera (606 species), and Bryozoa (520 species) representing those with more than 500 species. Analysis of the CTFB database can facilitate and direct efforts towards the discovery of new species in Brazil, but it is also fundamental in providing the best available list of valid nominal species to users, including those in science, health, conservation efforts, and any initiative involving animals. The importance of the CTFB is evidenced by the elevated number of citations in the scientific literature in diverse areas of biology, law, anthropology, education, forensic science, and veterinary science, among others

Sharing and community curation of mass spectrometry data with Global Natural Products Social Molecular Networking

The potential of the diverse chemistries present in natural products (NP) for biotechnology and medicine remains untapped because NP databases are not searchable with raw data and the NP community has no way to share data other than in published papers. Although mass spectrometry techniques are well-suited to high-throughput characterization of natural products, there is a pressing need for an infrastructure to enable sharing and curation of data. We present Global Natural Products Social molecular networking (GNPS, http://gnps.ucsd.edu), an open-access knowledge base for community wide organization and sharing of raw, processed or identified tandem mass (MS/MS) spectrometry data. In GNPS crowdsourced curation of freely available community-wide reference MS libraries will underpin improved annotations. Data-driven social-networking should facilitate identification of spectra and foster collaborations. We also introduce the concept of ‘living data’ through continuous reanalysis of deposited data