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Two hundred and forty-five samples of honey representing different botanical types were microbiologically tested for total number of aerobic bacteria, Salmonella sp., anaerobic bacteria, yeasts, and moulds. The samples presented different level of microbiological contamination. Total number of aerobic bacteria varied from 1.0 x 10¹ cfu/g to 7.5 x 10⁴ cfu/g. Salmonella sp. was not detected in any of the 25 g samples. Anaerobic spore forming bacteria were detected in 14.3% to 36.4% of samples, depending on the type of honey. Number of yeasts and moulds was low and only sporadically exceed 1.0 x 10² cfu/g.
During the last two decades antibiotic-resistant strains of Enterococcus spp. have emerged as important pathogens responsible for serious nosocomial infections in humans. From the medical point of view the resistance to vancomycin and aminoglycosides has special significance. Several studies suggest that resistant strains of enterococci could be transmitted from animals to humans through the food chain. In the Polish literature there is no data about antibiotic sensitivity of enterococci isolated from food of animal origin. The aim of the study was the evaluation of antibiotic susceptibility of enterococci recovered from different types of such food. One hundred and thirty eight strains of Enterococcus spp. obtained from regional veterinary laboratories were tested using the disk diffusion method. All strains were isolated from food of animal origin (milk and milk products, raw meat, minced meat). The percentage of resistant strains ranged from 2.2 for ampicillin to 84.1 for streptomycin. Most of the strains (133 isolates) were resistant for two or more antibacterial substances. The obtained results confirmed a relatively high level of resistance of enterococci for antibiotics used in animals and humans.
The results of microbiological analysis of 40 215 samples of milk and milk products examined in veterinary laboratories in 1994-1996 are described. It was found that 17.7% of examined samples did not meet the requirements of Polish Standards in regard to microbiological criteria. The main factors causing sample disqualifications were bacterial contamination and coliform bacteria which result from the low level of hygiene of milking and milk processing in dairy plants. In 1996, the results of examination of bacterial contamination of raw milk were analysed. The results indicated that only 58.6% of milk samples from individual producers and 63.3% of collected milk samples meet first class requirements. The results of the detection of inhibitory substances in raw milk and milk products are also described. These substances were detected in official examinations carried out by the Veterinaiy Sanitary Inspection and in two monitoring testing programs. The results confirmed a relatively high level of contamination of milk by inhibitory substances.
Raw, inhibitors free milk was spiked with penicillin G, ampicillin, cloxacillin, and ceftiofur at the levels 1 × MRL, 1.5 × MRL, and 2 × MRL, and oxytetracycline at the levels 100 ppb (MRL), 500 ppb and 700 ppb. The samples were stored at 4 ± 2°C and -18 ± 2°C and were tested every day and week, respectively. The analyses were performed using microbiological diffusion test Delvotest SP-NL and receptor assay CHARM ROSA MRL BL/TET for the detection of ß-lactams and tetracyclines. In cooled samples antibiotics were detected up to 72 h. After this time, the samples were acidulated and not suitable for investigations. In frozen samples, depending on type and concentration of antibiotics, these substances were detected from one week (penicillin G - 4 ppb) to 35 weeks (ampicillin and ceftiofur).
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