Aktuelle Themen

Aktuelle Themen

Aktuelle Themen

Occurrence and antimicrobial resistance ­profile of Salmonella isolated from native fish slaughtered and commercialised in Brazil
Vorkommen und Antibiotikaresistenzprofil von Salmonellen aus in Brasilien geschlachteten und vermarkteten einheimischen Fischen

Brazil is one of the largest freshwater fish producers worldwide, producing and supplying thousands of tons to the entire population. Fish-carrying Salmonella has been implicated in foodborne disease worldwide. In this context, this study aimed to investigate the occurrence of Salmonella, identify the serotypes present in fish samples slaughtered and commercialized in Brazil, and evaluate the antimicrobial resistance profiles of the isolated strains. Fifty-two samples of commercialized native fish were evaluated by classical microbiological culture and by a multiplex PCR. Salmonella was isolated and detected in three (5.76%) of the 52 analyzed fish samples. We identified the presence of two uncommon serovars in fish samples: S. Abony and S. Schwarzengrund. This is a novel worldwide report on the occurrence of S. Abony in freshwater fish. All strains demonstrated a single resistance to sulphamethoxazole + trimethoprim. This study is crucial for Salmonella surveillance in the entire country and can provide data to formulate control measures for the effective treatment and prevention of foodborne and zoonotic pathogens.

Amino acid decarboxylase activity, biofilm formation and antibiotic resistance of gram-negative bacteria isolated from marine fish, calf meat and chicken
Aminosäuren-Dekarboxylase-Aktivität, Biofilmbildung und Antibiotikaresistenz gramnegativer Bakterien isoliert aus Meeresfischen, Kalbs- und Hähnchenfleisch

The present study was carried out to test amino acid decarboxylase activity, biofilm formation and antibiotic resistance of 404 Gram-negative bacteria isolated from ­marine fish, minced veal and chicken. The following isolates were identified: Esherichia coli, Enterobacter cloacae, Klebsiella oxytoca, Citrobacter freundii, Hafnia alvei, Serratia marcescens, Pantoea agglomerans, Serratia fanticola, Proteus vulgaris, Citrobacter amalonaticus, Rahnella aquatilis, Morganella morganii, Escherichia vulneris, Klebsiella pneumoniae, Providencia rettgeri, Aeromonas hydrophila, Aeromonas caviae, Pseudomonas aeruginosa, Pseudomonas putida, Pseudomonas fluorescens, Pseudomonas oryzihabitans, Acinetobacter lwoffii, Acinetobacter baumannii and Shewanella putrefaciens. Two E. coli O157 isolates were isolated from minced veal. Decarboxylase activity was quite common for Gram-negative bacteria and over 70% of isolates could decarboxylate at least one amino acid, and lysine was the most frequently decarboxylated amino acid. According to our results, 60.3% and 62.6% of the Gram-negative bacteria produced slime and biofilm, respectively. In the antimicrobial susceptibility test, the isolates were highly resistant to ampicillin, and ß-lactamase inhibitors. Multiple antibiotic resistance indices are ranged from 0.29 to 0.64, suggesting exposure to antibiotic contamination. One hundred forty four (35.6%) out of 404 isolates were identified as extended spectrum ß-lactamase (ESBL)-producers.

Danijela A. Kostic, Snezana Mitic, Milan Mitic, Emilija Pecev Marinkovic, Ivana Rasic Misic, Biljana Arsic, Gordana Stojanovic
A new kinetic method using UV-VIS spectrophotometry for determination of caffeic acid in propolis
Ein neues kinetisches Verfahren zur Bestimmung von Kaffeesäure in Propolis mittels UV-VIS-Spektrophotometrie

The aim of this work is to develop an application kinetic-spectrophotometric procedure for the determination of caffeic acid (CA) in propolis. The method is based on oxidation reaction of CA by hydrogen peroxide in the presence of Cu (II) ions in alkaline solution. The reaction was monitored spectrophotometrically by measuring the rate of change of absorbance at 345 nm. The optimum operating conditions for reagent concentrations and temperature were established. Linear calibration curve was obtained in the range of 1.94 to 19.4 µg/ml with standard deviation from 2.77 to 4.15 %. The optimized ­conditions yielded a theoretical detection limit of 0.6 µg/ml based on 3.3So criterion. The developed method is sensitive, accurate and reproducible and could be used for routine analysis of CA in propolis.

Chandan Solanki, Dhritiman Saha, Ranjeet Singh
Moisture dependent physical properties of dehusked unsplitted pigeon pea
Feuchtigkeitsabhängige physikalische Eigenschaften von geschälten, nicht geteilten Straucherbsen

Pigeon pea (Cajanus cajan, L.) is an important legume crop in semiarid tropics generally consumed as dried peas for making dhal, flour or green vegetable peas. Dehusked unsplitted pigeon pea also called gota are obtained during the primary processing for making dhal. Hence, the knowledge about the physical properties of gota is important for designing processing machineries. In this regard, the study of the physical properties of gota (dehusked unsplitted pigeon pea) in the moisture content range of 10.2–28.2% d.b. was conducted. Five different levels of moisture content in the above range were selected. The average length, width, thickness, arithmetic mean diameter, geometric mean diameter, sphericity surface area, volume, thousand seed weight, bulk density, true density, porosity, angle of repose and coefficient of friction on plywood, mild steel and galvanized iron were determined in this moisture range. The values of average length, width, thickness, arithmetic mean diameter, geometric mean diameter, sphericity and surface area varied from 5.33 to 5.43mm, 4.39 to 4.45mm, 3.93 to 3.77mm, 4.51 to 4.55mm, 4.88 to 4.5mm, 0.858 to 0.828 and 63.29 to 63.73mm2 respectively. At the given moisture levels, volume, thousand seeds weight ranged from 38.41 to 40.77mm3, 61.94g to 68.93g in the same moisture range, the bulk density and true density decreased linearly from 859.5 to 781.7 kg/m3 and 1306.6 to 1128 kg/m3 respectively and porosity decreased non linearly from 34.22 to 30.2%. The static coefficient of friction of gota over different materials, namely plywood, mild steel and galvanized iron increased linearly from 0.4491 to 0.8405, 0.4789 to 0.7882 and 0.2851 to 0.6775 respectively. In the selected moisture range, the angle of repose increased from 28.35° to 36.72°.