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1.
The microbiological quality of 92 samples from the Oncological Service of a National Hospital, San José, Costa Rica was evaluated during the months of February to July, 2002. Of these samples, 48 were from salads, refreshments, and fruits and 44 from surfaces, air and hands of the medical personnel. The presence of total and fecal coliforms was determined by the total plate count technique, using Violet Red Bile Agar for the isolation of total and fecal coliforms, Baird-Parker Agar for Staphylococcus aureus, Cetrimide Agar for Pseudomonas and Listeria was enriched in University of Vermont Broth, Fraizer Broth and isolated in Oxford Agar. From the food samples analyzed, 77% were positive for at least one of the parameters studied; the fruits presented the greater contamination (94%) and the cooked salads the minor, even though Listeria was isolated in 13% of them. All tested salads (100%) were positive for fecal coliforms. Pseudomonas and S. aureus were isolated from fruits, raw salads, and refreshments. All the analyzed surfaces, with an exception, were negative for the parameters evaluated. 75% of the hands of the medical personnel were positive for at least one of the parameters evaluated; 25% had total coliforms (2.8x10(3) UFC/hand), 13% fecal coliforms (2.4x10(3) UFC/ hand), 69% S. aureus (1.3x10(3) UFC/hand) and 19% Pseudomonas sp. 115 isolates were randomly selected, and identified using miniaturized tests (API). When comparing these identifications with the 166 isolations done at the Clinical Laboratory of the Hospital from the infected patients of oncology, by means of variance analysis, it was determined that both bacterial populations were statistically similar.  相似文献   

2.
Ready-to-eat (RTE) foods are processed foodstuffs which have gained popularity in recent times because they can be ingested without further thermic treatments. In this work, the microbiological quality and safety of 90 samples of RTE foods manufactured by small Costa Rican industries was determined to evaluate whether they represent a Public Health risk. Twenty-six samples of pickled vegetables, 18 dips, 18 salads, and 12 sweet treats were studied. Each sample was analyzed with regard to its pH, the presence of culturable microbiological quality indicators and recognized foodborne pathogens (Salmonella, Listeria monocytogenes. Clostridium perfringens, C. botulinum, and Bacillus cereus) Selected genes encoding toxins of C. botulinum and C. perfringens were screened by PCR. Thirty-seven percent of the samples had a level of acidity that could allow the growth and proliferation of bacterial pathogens (pH > or = 4.5). The shelf-life indicators were acceptable but only if the RTE foods are kept at adequate conditions of temperature and humidity. Sixty-four percent of the RTE foods had total coliforms values that evidence inadequate hygiene practices during its elaboration (MPN/g >1000). This result was confirmed by the finding of fecal coliforms in 56% of the samples, which, by the way, are inacceptable for human consumption. All cultures for pathogens were negative, except for 4 samples that contained B. cereus. Toxins of C. botulinum were not detected and one single sample was positive for the PCR for C. perfringens. The elevated degree of fecal contamination detected in the RTE could be prevented by means of good manufacturing practices, better hygiene measures and a deeper attention to critical control points.  相似文献   

3.
The presence of Clostridium perfringens in eight slaughter houses from Costa Rica was analyzed using the Most Probable Number (MPN) technique, in order to assess the risk of acquiring a food borne intoxication due to consumption of contaminated meat. C. perfringens was detected in 29 (88%) out of 33 soil samples collected from the slaughter house surroundings (average 6.7 x 10(2) MPN/g), as well as in 70 (93%) out of 75 intestinal contents of slaughtered animals (average 3 x 10(4) MPN/g), in 42 (55%) out of 76 samples of slaughtered meat (average 2.2 x 10(4) MPN/g) and in 30 (61%) out of 49 retail meats (average 8 x 10(3) MPN/g). In addition, the presence of this bacterium was evaluated in ten retail meat markets located in the Metropolitan Area of Costa Rica, where it was isolated from 15 (75%) out of 20 samples of ground meat and from 28 (36%) de 78 stew meat samples (average 1.9 x 10(3) and 7.5 x 10(2) MPN/g, respectively). Only one out of 35 samples of cooked meat obtained from 32 restaurants that utilize heated water baths (average temperature of 82 degrees C) was positive for C. perfringens (4 MPN/g, temperature 72 degrees C). Out of 1121 bacterial isolates obtained, 250 were evaluated for enterotoxigenicity. Only 3 (1.2%) of these tested positive for enterotoxin production, probably because most wild strains are not toxin producers, even though they can be induced to produce it as a result of repeated thermal shocks. The present results urge the adoption of adequate preventive measures and high sanitary standards in the meat processing industry in Costa Rica, in order to minimize the risk of food-borne intoxications caused by C. perfringens, due to its widespread distribution and potential human health hazard.  相似文献   

4.
The demand of vegetables minimally processed (ready-to-use) has increased partly due to the frequent use of the food services, where the salads are always included in the daily menus. The use of new technologies for processing and packaging has made possible to obtain a product ready to serve. Nevertheless the associated risk of the presence of emergent pathogens, such as Listeria monocytogenes seems to be involved. The aim of this work was to assess the microbiological quality of this kind of food. 120 samples of vegetables minimally processed ready-to-use were analyzed for their content of aerobic mesophilic bacteria, total and fecal coliforms and E. coli, and the presence of Shigella spp. Vibrio cholerae and Listeria monocytogenes. The TECRA UNIQUE LISTERIA, the BCM Listeria monocytogenes and the API LISTERIA systems, and the methods of molecular detection AccuProbe and GENE-TRAK were used for isolation and identification. E. coli was detected in approximately 30.3% of the vegetables used in this study. The genus Listeria was evidenced in 25% of the samples; 30% corresponded to L. monocytogenes. Shigella spp and Vibrio cholerae were not isolated. The findings of this study suggest the need of the microbiological control of the vegetables minimally processed ready-to-use to assure their quality and safety.  相似文献   

5.
Enteral feeding is the most common and preferred modality for providing nutritional support to hospital patients with a functional gastrointestinal tract that can not satisfy their nutritional requirements. Nevertheless, enteral feeding may be an important cause of bacterial infection. The aim of this study was to evaluate the microbial contamination level of enteral feedings distributed in Costa Rican hospitals. A total of 124 samples of enteral feeding, coming from five different hospitals from San José, Costa Rica, were evaluated during the second semester of 1997 and first of 1998 for the presence and identification of total and fecal coliforms, Pseudomonas sp. and Listeria sp. A subpopulation of the Pseudomonas isolated was analyzed for their antibiotic susceptibility patterns. The concentration of Gram negative rods in the samples of enteral feeding solutions ranged from 10(3) to 10(7) CFU/mL, markedly exceeding the permissible level (10(2) CFU/mL or less). The coliforms most frequently isolated included Enterobacter cloacae, Escherichia coil, Serratia sp. and Klebsiella pneumoniae. Pseudomonas sp. was isolated in more than 70% of the samples made from commercial based solutions, fruits and vegetables. P. aeruginosa and P. fluorescens were the species most frequently isolated. Listeria sp. was not isolated from enteral solutions samples. The results obtained demonstrate that it is urgent to assure strict hygiene during the preparation and handling of all enteral feed in order to avoid bacterial growth. The implementation of HACCP (Hazard Analysis and Critical Control Points) system will be required in a near future for better quality control of enteral nutrition mixtures.  相似文献   

6.
Enteral feeding is the most common and preferred modality for providing nutritional support to hospital patients with a functional gastrointestinal tract that can not satisfy their nutritional requirements. Nevertheless, enteral feeding may be an important cause of bacterial infection. The aim of this study was to evaluate the microbial contamination level of enteral feedings distributed in Costa Rican hospitals. A total of 124 samples of enteral feeding, coming from five different hospitals from San José, Costa Rica, were evaluated during the second semester of 1997 and first of 1998 for the presence and identification of total and fecal coliforms, Pseudomonas sp. and Listeria sp. A subpopulation of the Pseudomonas isolated was analyzed for their antibiotic susceptibility patterns. The concentration of Gram negative rods in the samples of enteral feeding solutions ranged from 10(3) to 10(7) CFU/mL, markedly exceeding the permissible level (10(2) CFU/mL or less). The coliforms most frequently isolated included Enterobacter cloacae, Escherichia coil, Serratia sp. and Klebsiella pnuemoniae, Pseudomonas sp. was isolated in more than 70% of the samples made from commercial based solutions, fruits and vegetables. P. aeruginosa and P. fluorescens were the species most frequently isolated. Listeria sp. was not isolated from enteral solutions samples. The results obtained demonstrate that it is urgent to assure strict hygiene during the preparation and handling of all enteral feed in order to avoid bacterial growth. The implementation of HACCP (Hazard Analysis and Critical Control Points) system will be required in a near future for better quality control of enteral nutrition mixtures.  相似文献   

7.
The presence of Cyclospora sp., Cryptosporidium sp. and microsporidia and the levels of fecal coliforms were determined in lettuce, parsley, cilantro, strawberries and blackberries acquired in local agricultural markets of the Central Valley of Costa Rica, in order to establish the possible transmission risk of these microorganisms and other pathogens from the consumption of these raw products. During the second semester of 2001 and the first of 2002, 50 different samples of each product, 25 taken in the dry season and 25 in the rainy season and coming from five different local agricultural markets were evaluated. The fecal coliforms count was done according to the technique recommended by Vanderzant & Splittstoesser. The parasite determination was done using Zielh Nielsen and Weber staining techniques from a sediment obtained through the rinse of the mentioned products, using sterile peptonated water 0.1% and centrifuging at 900 G for 15 min. One hundred per cent of vegetable samples had fecal coliforms and the greatest prevalence was obtained during the rainy season. Although all vegetables presented fecal coliforms in high concentrations, lettuce and cilantro presented statistical difference between rainy and dry season, being greater during the rainy season. Fecal coliforms were not detected in strawberries and blackberries probablydue to its low pH. All products evaluated presented, at least once, Cryptosporidium sp., Cyclospora sp. and microsporidia, showing the risk they represent to Public Health. Cryptosporidium was present in all products but strawberries. Microsporidia was present in all products except blackberries and Cyclospora was only isolated from lettuce during the dry season. These results show the importance of introducing in the country Good Agricultural Practices, especially due to the resistance of Cryptosporidium and Cyclospora to disinfecting agents.  相似文献   

8.
一株脂肪酶产生菌及其脂肪酶催化性质的初步研究   总被引:1,自引:0,他引:1  
从各种含油脂的土壤中筛选分离到一株高选择性拆分(R,S)-2-羟基-4-苯基丁酸乙酯[(R,S)-HPBE]的产脂肪酶菌株CF-12,经形态观察、生理生化试验和16S rDNA序列分析,鉴定该菌为沙雷氏菌属(Serratia sp.)。对菌株CF-12产脂肪酶的发酵条件进行了初步优化,确定最适产酶条件为:蔗糖5 g/L,酵母粉10 g/L,金属离子Mg2+ 0.75 mmol/L,发酵培养24 h,脂肪酶活性可达20.1 U/mL。该脂肪酶最适反应温度和pH值分别为40 ℃和7.0。利用冻干酶粉拆分 (R,S)-HPBE 15 h,(R)-HPBE产率达39.6%,ee=90.8%。  相似文献   

9.
The microbiological quality of 205 samples of home-made cheese prepared from raw milk in six rural zones of Costa Rica was studied. In addition to determining their microbiological quality, recommendations are also issued for reducing to a minimum, the deficient sanitary conditions under which they are produced. Collection of samples was done directly at the producing farms. The following microbiological analyses were then undertaken: Staphylococcus aureus, thermonuclease (TNase) positive. Determination of most probable number (MPN) of coliform organisms of fecal origin. Total count of molds and yeasts, and Enumeration of mesophilic aerobic bacteria. As the data revealed, all samples contained high counts of the four microorganisms investigated, therefore demonstrating the deficient microbiological quality of the home-made cheese. On the basis of results obtained, a series of practical recommendations are suggested to improve the poor sanitary conditions under which they are now prepared.  相似文献   

10.
Unintended infestation of food with viable mould irreversibly leads to spoilage of food. However, little data existed on the fatty acid composition and polar lipid content of mould grown on cheese and the potential influence of these parameters in mould‐infested cheese. In this study, we thus focused on the fatty acids composition and polar lipid content of cheese, mould isolated from mould‐infested cheese, as well as inoculation of cheese with cultures of isolated moulds. For this purpose, we stored three cheese samples (gouda, brown cheese, and parmesan) over extended periods in order to force mould infestation from air. The moulds grown on gouda and brown cheese were identified as Penicillium brevicompactum and Penicillium roqueforti, respectively, while a mixed culture was obtained from parmesan. From these contaminated samples, mould spores were isolated and cultivated. Finally, the (pure) cheeses were inoculated with mould spores. Three subsamples, (1) cheeses, (2) moulds isolated from cheese, and (3) cheeses infested with the isolated moulds were studied with regards to their fatty acid distribution in the neutral and the polar lipids. The different amounts of polar lipids of cheese (0.39–2%), moulds (11–30.7%), and mould‐infested cheese (1.5–5%) allowed calculating the mould content of the mould‐infested cheeses.  相似文献   

11.
In this study, a set of municipal wastewater (MWW) samples from an actual residual water treatment plant was treated by ozone. The residual water was characterized in terms of organic load and biological contaminants: total coliforms (TC), fecal coliforms (FC) and helminth eggs (HE). Initial values of these parameters were 2.8 × 107 MPN/100 mL, 8.48 × 106 MPN/100 mL, and 470 L?1, respectively. The experimental setup considered the modification of pH and ozone dose as independent variables. Three different initial pH values (4.0, 7.0, and 11.0) and three different ozone concentrations (6, 15, and 30 mg/L) were used to investigate the pH ozone dose effect. The efficiency of ozone-based treatment was determined by the reduction of the microbiological indicators (TC, FC, and HE) and physicochemical parameters (COD and turbidity). The response surface method was used to determine suboptimal reaction conditions. These conditions were obtained using a two-stage procedure. The conditions under which both microbiological and organics were better removed corresponded to pH 7.8 and ozone concentration of 15.5 mg/L. A decline of biological indicators of 99% for TC, 99% for FC, and 99% for HE was obtained under the same reaction conditions. The reduction of chemical oxygen demand (COD) and turbidity was 75% and 85% under the same operation conditions, respectively.  相似文献   

12.
ABSTRACT

PAHs are aromatic hydrocarbons with two or more fused benzene rings. They are formed during the thermal breakdown of organic molecules and their succeeding recombination. Naphthalene is the simplest (PAHs) that is carcinogenic. Bioremediation method is considered as an economical and safe approach for the elimination of aromatic compounds from environment. The bacteria were capable to grow on various hydrocarbons like naphthalene. The aim of this research is to isolate and identify naphthalene-degrading bacteria from the coal mine of Zarand. Four samples of water and sludge from various sites of the mine were collected. These sites include the following: Main coal vacate site (MC), Inoculum Sump site (IB), Sludge aggregate site (SA), and Near sludge aggregate site (NF). In this study, 12 bacterial strains that utilize naphthalene at initial concentration 200 mg/L (ppm) as carbon and energy sources for growth were isolated from the Zarand mine in Iran. In addition, bacterial cell density was assayed by measuring the OD600. In addition, total naphthalene-degrading bacteria were quantified with the most probable number (MPN) procedure using microtiter plates and the colony-forming unit (CFU) method. The results had shown that most of the naphthalene degrader bacteria aggregated in (SA) site. Six bacteria, isolated from wastewater and oil-contaminated soil showed great potential as naphthalene degraders up to 400 (ppm) and selected for biochemical characteristics. Naphthalene tolerance of the strains in various concentrations of naphthalene indicates that the strain 38 N can grow best at 600 (ppm) naphthalene. This strain was identified based on 16S rRNA gene analysis that showed belonging to Sphingobacterium multivorum AHB38N.  相似文献   

13.
几种蔬菜中亚硝酸盐含量的测定   总被引:1,自引:0,他引:1  
用盐酸萘乙二胺比色法分别测定10种蔬菜中亚硝酸盐的含量,结果表明,在λ=538nm处,该络合物具有最大吸光度,在0~1μg·mL-1范围内,亚硝酸盐含量x(μg)与吸光度A之间具有良好的线性关系,其线性方程为y=0.0282x+0.0015,相关系数r=0.9997.从测定的芫荽等10种蔬菜当中,亚硝酸含量最高的为茄子...  相似文献   

14.
In the present study, the products from the ozonation of three systems (ozonized coconut oil, ozonized coconut oil with water and ozonized coconut oil with ethanol) are characterized and compared statistically. Peroxide, acidity and viscosity indexes were determined. The reaction products were identified by 1H NMR and their antimicrobial activity was evaluated. The ozonized coconut oil with ethanol showed the highest peroxide and acidity indexes. This result suggests that in presence of ethanol a greater peroxide decomposition occurs leading to greater acid formation. The variation coefficients obtained in the analysis methods were smaller than 10%. Reaction products were identified as ozonides and aldehydes compounds. The highest action spectrum of antimicrobial activity by Staphylococcus aureus was obtained with the ozonized coconut oil with water and ethanol systems.  相似文献   

15.
从某石化炼油厂排污口的污泥中富集、筛选并分离纯化得到六株汽油降解菌。选取降解性能较好的两株菌X和Z进行初步研究,结果表明,X和z均能以汽油为唯一碳源和能源生长。通过摇瓶实验得出两株菌的最适生长条件:X为37℃,pH7.0,15%接种量,盐浓度(NaCl)为10g/L;Z为35℃,pH8.0,15%接种量,盐浓度(NaCl)为10g/L。经形态学观察和生理生化特征研究,初步确定X为假单胞菌属(Pseudomonassp),Z为芽孢杆菌属(Bacillus sp)。  相似文献   

16.
Fish constitutes a very important part of human diet due to its protein content. The poor commercialization system existing in Costa Rica for this product causes an important secondary contamination that may include microorganisms such as fecal coliforms, Staphylococcus aureus and even pathogens such as Listeria monocytogenes. There is a lack of recent information about the microbiological quality of the fish that arrives to the Metropolitan Area of San José, Costa Rica, so the aim of this work was to study it through the detection of microbiological indicators and the incidence of L. monocytogenes. Five different samplings were realized to 27 fisheries located in two different areas from San José, Costa Rica: the Central Market and the rest of the Metropolitan Area. Each time, a 500 g sample of fresh filleted fish was taken and transported to the Food Microbiology Laboratory, Universidad de Costa Rica, for performing the different analysis, which included the presence/absence of L. monocytogenes, total plate count, total and fecal coliforms count and Most Probable Number of Staphylococcus aureus. Also, a hygiene evaluation of the different fisheries was performed. According to this, 22.2% of the fisheries were classified as excellent, 14.8% as good, 40.8% as regular and 22.2% as bad. Fisheries hygiene is independent of the incidence of L. monocytogenes with a 95% confidence level, and there is no significant relationship between hygiene and the other indicators analyzed. There is a significant relationship between the incidence of Listeria sp. and the hygiene of the Central Market area. It was determined that 96.3% and 29.6% of the fisheries accomplish with the microbiological limits established by ICMSF for S. aureus and total plate count, respectively. Listeria sp. was found in 65.2% of the fish samples analyzed. From these, 52.3% was L. monocytogenes, 43.2% L. innocua, 3.4% L. ivanovii and 1.1% L. seeligeri. In 88.9% of the fisheries the presence of L. monocytogenes was positive at least once.  相似文献   

17.
The sex pheromone of the American cockroach,Periplaneta americana, consists of two compounds, which we have named periplanone-A and periplanone-B. The two compounds can be isolated from fecal material in a ratio of 110, and periplanone-B can also be isolated from intestinal tracts. A total amount of 200 g of periplanone-B has been isolated from both fecal material and alimentary tracts. By means of gas chromatography-mass spectrometry, hydrogenation, infrared analysis, and NMR analysis, we were able to identify periplanone-B as (1Z,5E)-1,10(14)-diepoxy-4(15),5-germacradien-9-one. The overall structure was confirmed by comparison with a synthetic, biologically active epimer of periplanone-B.  相似文献   

18.
The evaluation of the microbiological charge present in Costa Rican samples as the evaluation of its antimicrobial activity over different microorganisms, including those associated to wound infections, will allow to emit criteria referred to its use in therapeutic treatments, specially as alternative therapy for cases involving antibiotic resistant bacteria. The microbiological charge of 25 honey samples, acquired in Costa Rican markets was evaluated through several indicators including total plate aerobic count, total plate anaerobic count, total aerobic spore count, total anaerobic spore count and molds and yeast count. Also, samples were inoculated in tubes with chopped meat media and plated in egg yolk agar in order to determine the presence of Clostridium botulinum. For the antimicrobial activity evaluation, the diffusion method in Muller Hinton agar was performed, testing different honey concentrations (100, 75, 50, 25, 12,5 and 6,25 % v/v) against Staphylococcus aureus (ATCC 25923), Staphylococcus epidermidis (UCR 2902), Pseudomonas aeruginosa (ATCC 9027), Escherichia coli (ATCC25922), Salmonella enteritidis (ATCC 13076), Listeria monocytogenes (ATCC 19116) and Aspergillus niger. The results obtained for the microbiological characterization of honey show that 91% of samples had counts equal or lower than 1,0 x 10(1) CFU/g. No positive result was obtained for the isolation of C. botulinum. 24 of the samples analyzed inhibited the growth of S. aureus even in a 25% v/v concentration, nevertheless, A. niger was no inhibited by any of the samples tested.  相似文献   

19.
This study aimed to examine the possibility of producing marmalades from the fruit pulp of the red and white varieties of card6n dato (Stenocereus griseus). We developed the formulations of the marmalades and evaluated their stability during three months of storage at room temperature. As first step, we characterized the fruits of the two color varieties, observing that despite the considerable difference between both color varieties, there were no significant differences in average weight, dimensions and proportion of pulp, skin and seeds. The pulp of the two color types had high pH (5.2) values and low contents of reductor sugars (3.59 g/ 100 g white variety 2.23 g/ 100 g red variety), non reductor sugars (0.75 g/ 100 g white variety and 2.03 g/ 100 g red variety), pectin (0.14 g/ 100 g white variety and 0.23 g/ 100 g red variety) and acids (7.67 g/ 100 g white variety and 0.15 g/ 100 g red variety). It is needed to include sugar, pectin, and citric acid in the marmalade formula. The first marmalades produced were gummy, a problem that we solved adding the acid from the beginning of the making process. During the three months of storage, the marmalades had good acceptance by the evaluators, this despite slight fluctuations observed in pH, solid contents, and acidity.  相似文献   

20.
A new cyclic hexapeptide, baceridin ( 1 ), was isolated from the culture medium of a plant‐associated Bacillus strain. The structure of 1 was elucidated by HR‐HPLC‐MS and 1D and 2D NMR experiments and confirmed by ESI MS/MS sequence analysis of the corresponding linear hexapeptide 2 . The absolute configurations of the amino acid residues were determined after derivatization by GC‐MS and Marfey's method. The cyclopeptide 1 consists partially of nonribosomal‐derived D ‐ and allo‐D ‐configured amino acids. The order of the D ‐ and L ‐leucine residues within the sequence cyclo(‐L ‐Trp‐D ‐Ala‐D ‐allo‐Ile‐L ‐Val‐D ‐Leu‐L ‐Leu‐) was assigned by total synthesis of the two possible stereoisomers. Baceridin ( 1 ) was tested for antimicrobial and cytotoxic activity and displayed moderate cytotoxicity (1–2 μg mL?1) as well as weak activity against Staphylococcus aureus. However, it was identified to be a proteasome inhibitor that inhibits cell cycle progression and induces apoptosis in tumor cells by a p53‐independent pathway.  相似文献   

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