98 resultados para SCINTILLATION COUNTING
Resumo:
The purpose of this study was to verify and compare the main contamination sources and the hygienic/sanitary conditions of organic honey samples of Apis mellifera from Parana River islands. Thirty-three (33) samples were analyzed between January 2005 and August 2006. Eleven (11) samples were collected by beekeepers and twenty-two (22) samples were collected and processed in accordance with ideal personal hygiene norms and good manufacturing practices. The samples underwent microbiological analysis in search of coliforms at 35 ºC and 45 ºC, as well as fungi enumeration analysis. As for fungi counting, the samples harvested by beekeepers showed values above the maximum established by Resolution nº 15/94 of Common Market Group - Mercosul. The results showed that secondary contamination sources are responsible for the reduction of organic honey quality.
Resumo:
Halotolerant or halophilic (Archaeabacteria) microorganisms can be found in salted and ripening fish products that are not affected by salt. They can be moderate or extremely halophilic bacteria. The extremely halophilic bacteria require between 15-30% of NaCl for growth. The extremely halophilic archaeobacteria may be selectively isolated in different media. The aim of this work was to determine the effectiveness of the Salt-Agar-Milk medium, a medium modified in our laboratory through the addition of MgSO4 and KCl - named SAMm, and its effect on the bacterial growth by means of comparison with other media, with and without milk, determining time of incubation and counting. Two samples of salted fish from local fish salting factories and two laboratory strains were used. The factory samples were matured anchovy and anchovy fillets in oil, and the laboratory strains were: Haloarcula spp. (proteolytic) and Halococcus spp. (non-proteolytic). The following media were alternatively used for the isolation of extremely halophilic bacteria: IRAM; Formulation of Gibbons and collaborators, Cod Milk agar, and SAMm. IRAM and Gibbons were also used enriched with milk. In the SAMm medium, there were obtained count values similar or higher than the ones of the traditional media; besides the simplicity of its elaboration, the possibility to obtain positive results two or three days earlier also added to its benefit. Consequently, it can be considered an alternative to the media traditionally used for the studied halophilic bacteria.
Resumo:
Rice bran is a byproduct commonly used for animal feeding; however its nutritional value and potential application in human diet have attracted market interest. Its preservation for safe use is still a challenge, so the objective of this study was to determine the quality of commercially available rice bran samples subjected to different heat treatments (extruding, parboiling, toasting, and microwave oven heating) in order to promote stabilization during storage under room temperature. Rice bran samples were collected from two industries, and each treatment was divided in three parts, each corresponding to three repetitions. All samples were evaluated for moisture content, total microorganisms, mold and yeast counting, hydrolytic rancidity, and lipase activity during 90 days of storage. Most of the heat treatments, including domestic and thermoplastic extrusion, generated products which may be used for human consumption under the tested conditions in terms of physicochemical and microbiological quality. The domestic treatments were more efficient in eliminating microorganisms or keeping them within acceptable limits. The toasted rice bran showed satisfactory results in terms of moisture, hydrolytic rancidity control, and lipase activity.
Resumo:
The objective of this study was to investigate the influence of storage conditions on the physicochemical (mass, albumen height, pH, and Haugh unit) and microbiological (Salmonella spp., determination of the Total and Thermotolerant Coliforms, and Counting of the Mesophilic Aerobic Bacteria) quality of eggs. In the first experiment, a questionnaire was applied, and 33 samples of eggs were collected for the Salmonella spp analysis. In the second experiment, the eggs were collected from supermarkets, open markets, and distributors for physicochemical analysis. In the third experiment, 175 eggs were collected from the distributor, packaged in cardboard boxes lined with plastic wrapping, stored at 5 °C and 28 °C, and the physicochemical and microbiological analyses were performed at 7, 14, and 21 days of storage. In the first experiment, 100% of the samples analyzed showed no Salmonella spp. In the second experiment, it was found that the values of physicochemical parameters were in agreement with those in the literature. However, in the third experiment, the physicochemical parameter results showed statistical difference during storage and temperatures studied. Salmonella spp. were found in the samples stored at room temperature and in the refrigerated samples. Mesophilic microorganisms with values ranging from <10 CFU g- 1 (estimated) to 8.0 × 10³ CFU g- 1 and coliforms to 4 NMP.g- 1 were also found, but the presence of E. coli was not confirmed.
Resumo:
The objective of this study was to evaluate the applicability of the Petrifilm™ plates to enumerate microbial groups in sheep milk. Samples of sheep milk (n = 30) were plated simultaneously, to enumerate mesophilic aerobes, total coliforms, lactic acid bacteria, Staphylococcus aureus and Escherichia coli, using convencional reference protocols and Petrifilm™ plates. The results were compared using McNemar's test, linear regression and ANOVA (p < 0,05). The results demonstrated good significant between conventional methodologies and Petrifilm™ plates. Further, the Petrifim™ STX for counting S. aureus had higher recoverability of bacteria compared with the conventional methodology. Based on the results obtained and in view of the ease and rapidity procedures results, Petrifim ™ plates may be considered as alternatives for microbiological testing in sheep milk.
Resumo:
Abstract There are no precedents concerning the quality of Octopus maya during chilled storage. This study evaluated the shelf life of the red octopus in chilling storage (4oC) and the correlation of the sensory quality index with microbiological counting and the biochemical indicators (hypoxanthine, histamine and volatile amines). A total of 112 whole raw octopi (average weight of 896 g) were randomly selected from seven batches and exposed to 4°C for 18, 24, 48, 72, 84, 96, and 100 h. The histamine concentration (91.7%), followed by the counts of psychrotrophic bacteria (5.5%) and hypoxanthine (2.2%), were the predictors from the redundancy analysis that better explained the changes taking place during the chilling hours. After 72 h of chilling, the microbial count was determined to be log 4.7 CFU/g, and the octopus samples were classified as B quality (minor sensory quality defects) based on the sensory quality scale. Although the samples were not classified as unacceptable at 100 h of refrigeration by the sensory index, the level of histamine reached the defect action level (5 mg/100 g) as ruled by the International Food Safety Authorities. The shelf life of the red octopus in chilling storage was predicted to be 119 h.
Resumo:
This work aimed to evoluate physiological response of cowpea (Vigna unguiculata L. Walp) seeds submitted to salt stress. Seeds of cultivars 'Epace-10'; 'Canapu' and 'Pitiúba' of cowpea, were submitted to germination test in germinator at 25(0)C, in "germitest" papers imbibed in distilled water or in 0, 10, 50, 100 and 200mol m-3 NaCl solutions. At the first and second counting of the germination test, normal seedlings were accounted, weighted and dried, obtaining data for vigor, total germination, fresh matter weight and dry matter weight. The seedlings hypocotyls, root and total length were measured total proteins content in cotyledons were obtained from germinating seeds. The presence of salt at concentrations higher than 50mol m-3 NaCl affect the germination, seedlings growth and cotyledons total protein synthesis of all cowpea cultivars. The seeds of cultivar pitiúba were is more tolerant to salinity, than the cultivars Canapu and Epace-10.
Resumo:
The main objective of seed coating technology using polymers is to improve the physical, physiological and sanitary characteristics of seed performance. The objectives of the present study were to determine: the plantability of corn seeds treated with insecticide, fungicide and graphite, covered with a film coating; the dust retention on treated corn seeds; and the leaching of applied products on corn seeds covered by a film coating. Seed plantability was determined by counting the skips and double seeds; dust was determined by using fiberglass paper in mg.100 g-1 of seeds; and the leaching was determined by collecting the material leached in a 10 cm layer of sand after irrigation. The following conclusions were made: seeds covered with film coating effectively reduce skips and double seeds; film coating effectively reduces the formation of dust from the seeds; film coated seeds minimize the leaching of the insecticide applied in seed treatment; and there are differences in effectiveness related to film coating type and dosage.