In this study, microbiological tests for the detection of beta-lactam antibiotics in meat and meat products were evaluated. The traditional FPT (four plate test, containing Bacillus subtilis and Kocuria rhizophila), BsDA (Bacillus stearothermophilus disc assay) and a newly developed microbiological test, Premi Test (containing Bacillus stearothermophilus) were included in the study. The limit of detection (LOD) of the Premi Test was compared with the LOD of the traditional methods. The detection limits of the tests were determined by using beta-lactam antibiotic standards dissolved in meat juice, as well as meat tissue obtained from laying hens after experimental administration of amoxicillin. Positive samples, based on inhibition of growth of the organism in the test, were confirmed by high performance liquid chromatography (HPLC). Growth inhibition in the traditional tests is visible as a clear zone on the plate, whereas for Premi Test, this is based on the absence of a colour change of the test. The LODs of antibiotics tested were as follows: Penicillin G (PENG) 5 microg kg(-1), amoxicillin (AMOX) 10 microg kg(-1), ampicillin (AMP) 25 microg kg(-1), oxacillin (OXA) 30 microg kg(-1), and cloxacillin (CLOX) 30 microg kg(-1) on the plate with Bacillus stearothermophilus. Beta-lactam antibiotics can be detected also on one plate seeded with Kocuria rhizophila, although the LODs are higher: PENG 10 microg kg(-1), AMOX 25 microg kg(-1), AMP 30 microg kg(-1), OXA 50 microg kg(-1), and CLOX 50 microg kg(-1). Premi Test was performed according to the Standard Operating Procedure intended for detection of beta-lactam antibiotics in poultry tissues with following LODs: PENG 4 microg kg(-1), AMOX 5 microg kg(-1), AMP 5 microg kg(-1), OXA 40 microg kg(-1), CLOX 50 microg kg(-1). All tests are able to detect beta-lactam antibiotics such as penicillin G, ampicillin, amoxicillin, oxacillin and cloxacillin below the maximum residue level (MRL). However, the detection limits of the Premi Test for PENG, AMOX and AMP were below the limits of BsDA and the plate containing Kocuria rhizophila.
One of the traditional plants that have so many pharmacological effects is chilli fruit (Capsicum sp.) that belong to the family Solanaceae. Around the world, five varieties of Capsicum are known, i. e., C. annuum, C. frutescens, C. chinense, C. baccatum, and C. pubescens. Chilli peppers are known for causing the sensation of heat or burning when consumed. The heat sensation is incited by the type and the amount of a group of capsaicinoids; the alkaloids found only in chilli pepper pods. A widely used heat measurement of chilli peppers is the SHU (Scoville Heating Unit). This measurement is the highest dilution of a chilli pepper extract at which heat can be detected by a taste panel. Nowadays, the Scoville organoleptic test has been largely replaced by chromatographic methods which are considered to be more reliable and accurate. The HPLC (High Pressure Liquid Chromatography) method was used for the determination of capsaicin content in various fresh and dried peppers from the genera C. chinense. Currently, based on the results of HPLC, the hottest pepper has been Bhut Jolokia, followed by Habanero Red Savina and Habanero Yellow etc. The content of capsaicin in dried chillies is 7-10 times higher compared to fresh ones.
The rainbow trout (Oncorhynchus mykiss) is considered as an important fish in the freshwater aquaculture and play a significant role in the human diet. The final quality of fish depends on the chemical and microbiological quality of fish at the time of freezing as well as on other factors including storage temperature and processing. The purpose of the study was to determine the microbiological status of 30 samples cooled and frozen trouts collected from approved farm in the Turiec region, territory of middle Slovakia. Total viable counts (TVCs), psychrotrophic bacteria, Pseudomonas spp. and also total volatile base-nitrogen (TVB-N) and pH were measured in samples of fresh (1. and 7. day of storage at 0 - 2 °C) and frozen whole trout and trout fillets. Frozen samples were stored at -18 °C during 1, 3, and 6 months. Samples were collected from the skin, muscles (sterile) and muscles after filleting. The microbiological quality of samples varied between fresh and frozen (6th month of storage) regarding TVCs and also between samples taken from the skin and muscles after filleting compared to muscle samples collected sterile regarding all tested bacteria. A large number of bacteria (pathogens and spoilage bacteria) enter with the raw material and in particular the skin contamination had a negative impact on the increase of microbial load in fillets. All processing techniques and procedures including filleting therefore must be designed and aimed to minimise contamination and growth of microorganisms in fish. However, based on the results of TVB-N analysis, differences between fresh and frozen samples were found, but all the samples were suitable for human consumption.
This study confirmed the need of monitoring antimicrobial resistance in coagulase-negative staphylococci not only in the meat of slaughter animals but also in retail marine fish. The results showed that MALDI-TOF mass spectrometry is useful, accurate, and rapid method for species identification of food pathogens including Staphylococcus spp.
The aim of this study was to determine susceptibility of species-identified coagulase-negative staphylococci (CoNS) isolated from the thigh muscles of hunted wild pheasants (Phasianus colchicus) to seven antibiotics (penicillin, tetracycline, erythromycin, ampicillin, oxacillin, gentamicin, and vancomycin) with the help of agar dilution method. Genus confirmation of each isolate was based on the analysis of PCR product obtained from DNA target 16S ribosomal DNA. Species-identification of staphylococci was performed by means of matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS) based on bacterial protein profiling. From the results of this study it follows that 41 strains of CoNS were isolated from the meat of wild pheasants. The following species of staphylococci were identified by MALDI-TOF MS: S. epidermidis (17 strains), S. warneri (8 strains), S. haemolyticus (5 strains), S. hominis (4 strains), S. xylosus (3 strains), S. vitulinus (2 strains), S. pasteuri (1 strain) and S. arlettae (1 strain). Based on results of the agar dilution method, resistance to penicillin was detected most frequently (96.2%). On the contrary, 100% susceptibility to vancomycin was observed among isolates of CoNS. Moreover, each out of 41 isolates showed simultaneous resistance to at least two antibiotics tested.
Penicillium species belong to main causative agents of food spoilage leading to significant economic losses and potential health risk for consumers. These fungi have been isolated from various food matrices, including table eggs. In this study, both conventional Polymerase Chain Reaction (PCR) and Polymerase Chain Reaction-Internal Transcribed Spacer-Restriction Fragment Length Polymorphism (PCR-ITS-RFLP) methods were used for species identification of Penicillium (P.) spp. isolated from the eggshells of moldy chicken eggs. Seven restriction endonucleases (Bsp1286I, XmaI, HaeIII, HinfI, MseI, SfcI, Hpy188I) were applied to create ribosomal restriction patterns of amplified ITS regions. To identify P. verrucosum, P. commune, and P. crustosum with the help of conventional PCR assay, species-specific primer pairs VERF/VERR, COMF/COMR, and CRUF/CRUR were designed on the base of 5.8 subunit-Internal Transcribed Spacer (5.8S-ITS) region. Altogether, 121 strains of microscopic filamentous fungi were isolated by traditional culture mycological examination. After morphological evaluation of both macroscopic and microscopic features, 96 strains were classified in Penicillium spp. Two molecular methods used have confirmed eight isolates as P. verrucosum, 42 isolates as P. commune, and 19 isolates as P. crustosum. Both PCR-ITS-RFLP and conventional PCR assays appear to be suitable alternatives for rapid identification of the above mentioned Penicillium species.
One of traditional plant that has so many pharmacology effects is chilli fruit (Capsicum sp.) that belong to the family Solanaceae. Around the world is known five varieties of Capsicum which are C. annuum, C. frutescens, C. chinense, C. baccatum, and C. pubescens. Chilli peppers are known for causing the sensation of heat or burning when consumed. The heat sensation is incited by the type and the amount of a group of capsaicinoids, the alkaloids found only in chilli pepper pods. The HPLC method was used for determination of capsaicin and dihydrocapsaicin content in various dried peppers from genera C. chinense. Based on the results of HPLC the hottest pepper has been Bhut Jolokia, followed by Habanero Red Savina, Fatalii Yellow, Habanero Paper Latern, Habanero Maya Red, Habanero Red, and Scotch Bonnet Red. The inhibitory effect of the extract of Capsicum chinense pepper type was evaluated, using dics diffusion method, against selected bacteria and micromycetes. Extracts from Bhut Jolokia, Fatalii Yellow, Scotch Bonnet Red and habaneros did not inhibit growth of the any bacteria and micromycetes included in our test.
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