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At least 199 records · Page 11Linked to original sources
PubMed1993

The growth and expression of virulence factors at refrigeration temperature by Aeromonas strains isolated from foods.

A potentially significant subset (10%, 6/61) of Aeromonas strains isolated from food (milk, lamb, chicken, seafood), all A. veronii biotype sobria, were able to produce two or more exotoxins (haemolysin, enterotoxin, and cytotoxin) at 37 degrees C, and grow well at 43 degrees C. Although mesophilic organisms, they grew at 5 degrees C. In addition, they could adhere to HEp-2 cells when grown at 37 degrees C, or at 5 degrees C, and expressed flexible pili (possible colonization factors) in greater numbers at the lower temperature. These strains, as well as other exotoxin-producing strains (A. veronii biotype sobria and A. hydrophila) (33%, 20/61) lacking adhesive ability, were able to produce cytotoxins in broth cultures over a seven to 10-day period at 5 degrees C. One strain in particular, an A. hydrophila isolated from goats' milk, grew rapidly at low temperature. This psychrotrophic strain produced all three exotoxins within 3 days in broth cultures at 5 degrees C. The properties of the above strains suggest they could be of public health significance in food products that have an extended shelf-life at refrigeration temperature.

Aeromonas↗
PubMed1992

Sterility of refrigerated injectable collagen syringes after injection of patient.

BACKGROUND: Injectable collagen has been used for more than 15 years to correct soft tissue cosmetic defects. After injection, the collagen remaining in the syringe is often refrigerated for later use in the same patient, despite manufacturer and Food and Drug Administration recommendations to discard the unused collagen. OBJECTIVE: This study examined the incidence of bacterial contamination of stored collagen. METHODS: Syringe needle tips and collagen from 50 previously used syringes containing either Zyderm I, Zyderm II, or Zyplast were cultured separately under aerobic and anaerobic conditions. Bacterial isolates were identified. RESULTS: Propionibacterium acnes was cultured from 7 of 50 needle tips. One positive needle tip culture grew both P. acnes and Staphylococcus aureus. Bacteria were isolated from only one collagen sample that grew a nonhemolytic streptococcus that may have represented a laboratory contaminant. CONCLUSION: Syringes of collagen stored for repeated use rarely become contaminated with bacteria despite frequent contamination of their needle tips. Skin abscesses after collagen injection should be cultured under anaerobic, as well as aerobic, conditions so that infections caused by P. acnes will not be missed.

Collagen↗
PubMed1994

Appraisal of the stability of leukocytes in refrigerated urine.

There is limited evidence that urinary leukocytes are rapidly destroyed in alkaline hypotonic urine. We assessed the stability of leukocytes in urine specimens provided by 90 children with neurogenic bladder who attended a meningomyelocele clinic. No significant correlation was found between urine specific gravity and leukocyte survival after an interval of 4 h in a sample of 30 specimens from these patients. The survival of leukocytes was determined at 2 h and at 4 h in aliquots of these 30 specimens directly, and after adjustment to pH values of 5.0, 7.0, 8.0, 8.5, and 9.0. Statistically significant leukocyte destruction only occurred at pH 9.0 at 2 h (16%), at pH 8.5 at 4 h (19%), and at pH 9.0 at 4 h (57%). Only one of a further sample of 180 routine specimens had both a pH of > or = 8.5 and an interval to laboratory examination of > 2 h. No specimen had a specific gravity of < 1.002, and 93.9% had values of > or = 1.005. Urine pH and tonicity were not therefore important determinants of leukocyte stability in refrigerated samples examined within 4 h from this clinic population.

Cell Survival↗
PubMed2005

Effect of storage period under variable conditions on the chemical and physical composition and colour of Spanish refrigerated orange juices.

The effects of the physicochemical and quality characteristics of various minimally pasteurized refrigerated orange Spanish juices and their changes with storage time and temperature were investigated. Essential oils, acidity, conductivity, diacetyl index, hydroxymethylfurfural, formol index, viscosity and ascorbic acid varied with storage time more significantly at 10 degrees C than at 4 degrees C. Density, colour and pectinmethylesterase did not vary at 4 degrees C. Some of the parameters could be used as indicators of quality loss or spoilage of the juices. The degradation kinetics of the concentration of remaining ascorbic acid against time follows a straight line whose slope indicates the degradation rate. A period of at least 42 days at 4 degrees C and 35 days at 10 degrees C was established as the shelf life of the juices.

Amino Acids↗
PubMed2006

Synergistic bactericidal effect of carvacrol, cinnamaldehyde or thymol and refrigeration to inhibit Bacillus cereus in carrot broth.

Possible use of three different essential oil components as natural food preservatives was studied by examining their influence in the kinetics of growth from activated spores of four Bacillus cereus strains in tyndallized carrot broth over the temperature range 5-16 degrees C. Selected low concentrations of carvacrol, cinnamaldehyde, or thymol showed a clear antibacterial activity against B. cereus in the vegetable substrate. The addition of 2 microl cinnamaldehyde or 20 mg thymol to 100 ml of broth in combination with refrigeration temperatures (<or= 8 degrees C) was able to inhibit the outgrowth from activated spores of the psychrotrophic strain INRA TZ415 for at least 60 days, but only cinnamaldehyde did it even at the mild abuse temperature of 12 degrees C. Five microliters of carvacrol per 100 ml of inoculated carrot broth, however, were unable to inhibit bacterial growth at 8 degrees C.

Acrolein↗
PubMed2006

Effect of acacia (Robinia pseudo-acacia L.) honey on the characteristic microflora of yogurt during refrigerated storage.

The primary purpose of this research was to monitor the influence of acacia honey addition to yogurt milk on survival of the microbial flora of yogurt during refrigerated storage for 6 wk. Results showed that the presence of honey at 1.0% to 5.0% (w/v) did not significantly influence (P>0.05) the viability of characteristic microorganisms (i.e., Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus) in yogurt during storage at 4 degrees C. Similarly, honey had no effect on pH and lactic acid levels of the final products. Despite these findings, enrichment of yogurt with honey is recommended because honey is a natural sweetener that possesses a wide range of beneficial nutritional properties. In addition, at a rate of approximately 3.0% (w/v), it highly improves the sensory quality of the finished product without having a detrimental effect on characteristic lactic acid bacteria.

Food Handling↗
PubMed2006

Genetic diversity of Gram-negative, proteolytic, psychrotrophic bacteria isolated from refrigerated raw milk.

The random amplified polymorphic DNA (RAPD) fingerprinting technique was used to assess the genetic diversity of 70 isolates of Gram-negative proteolytic psychrotrophic bacteria that were isolated from refrigerated raw milk. Three oligonucleotides, which generated 87 fragments of polymorphic DNA, were used in the amplification reactions. The genetic distance values calculated using Jaccard's coefficient showed there was high genetic variability among the isolates. Cluster analysis procedures suggested that the genetic variability among isolates belonging to the same species was as high as the variability among different species. Clustering by the UPGMA hierarchical method and data graph dispersion indicated a tendency of the isolates to group according to whether they did or did not ferment glucose.

Animals↗
PubMedDate not supplied

A novel system for organ and tissues preservation: the refrigerating hyperbaric chamber.

UNLABELLED: This study was designed to investigate the feasibility of building a simple and inexpensive device to preserve organs or tissues in hyperbaric and hypothermic conditions. METHODS: The device was built on a 40-cm wide, 28-cm long, and 23-cm deep stainless steel chassis. The pressure vessel was built by a 7.8-cm bore stainless steel cylinder put inside another 12-cm cylinder welded together and closed by a steel plate on the top and bottom. The inferior plate was welded, and the superior one was fixed by manual clasp nut. The cooling system is made up of air compressor, condenser, expansion area, and cooling worm that is located between the cylinders. The temperature-controlling device is a computer processor contained in an integrated-circuit chip, with a on-off system to maintain the chamber temperature between 2 degrees to 4 degrees C. The compression of the chamber is performed by lateral coupling with the oxygen cylinder and is maintained at 5.5 absolute atmospheres and controlled by air pressure gauge. The maximal work pressure was evaluated by spreadsheet. Temperature or pressure changes were evaluated by 12- and 24-hour assays. RESULTS: The maximal work pressure permitted was 6.5 absolute atmospheres. Thus, the container was free from danger. The temperature inside the chamber was kept between 2 degrees and 4 degrees C. The production costs of the prototype was US$1000. DISCUSSION: The manufacture of the refrigerating hyperbaric chamber is viable, simple, and inexpensive.

Cold Temperature↗
PubMed2005

Stability of influenza sub-unit vaccine. Does a couple of days outside the refrigerator matter?

In this study 27 full scale production batches of influenza sub-unit vaccine were evaluated on their stability. The batches varied with respect to the strains they contained and regarding the presence of the preservative thiomersal in the solution. The stability study showed that haemagglutinin content was the most sensitive parameter. An increase in the storage temperature strongly increased the degradation rate of haemagglutinin. The degradation rate of the haemagglutinin differed for the different strains tested. However, statistical evaluation of the data obtained for the most sensitive strain tested showed that even exposure during a 2 week period of the vaccine to room temperature would not adversely affect the shelf life claim of the influenza subunit vaccine of 1 year in the refrigerator. Moreover, this study showed that the presence of thiomersal in the solution has no effect on the stability of the vaccine.

Drug Stability↗
PubMed1985

Survey of refrigeration and surgical technics used for facial dermabrasion.

Concern has recently been expressed regarding the possibility of freeze-associated adverse effects (delayed healing, prolonged erythema, scarring) associated with the use of potent spray refrigerants used for dermabrasion. A survey was undertaken among experienced dermatologic surgeons in an attempt to define variations in technic that might explain the absence of universal difficulties with these products. Distance of spray nozzle to skin, attempted depth of abrasion, and ambient room temperature emerged as possible differences between the complication-free and complication-affected groups. Speculations relating these differences to freeze-associated adverse effects are presented.

Dermabrasion↗
PubMed2006

In vitro developmental competence of pig nuclear transferred embryos: effects of GFP transfection, refrigeration, cell cycle synchronization and shapes of donor cells.

The present study was designed to evaluate the feasibility of producing pig transgenic blastocysts expressing enhanced green fluorescent protein (GFP) and to examine the effects of shape and preparation methods of donor cells on in vitro developmental ability of pig nuclear transferred embryos (NTEs). In experiment 1, the effect of GFP transfection on development of pig NTEs was evaluated. The cleavage and blastocyst rates showed no significant difference between NTEs derived from transfected and non-transfected donors. In experiment 2, the effect of different nuclear donor preparation methods on in vitro development of NTEs was examined. The cleavage rate showed no statistically significant differences among three preparation methods. The blastocyst rates of donor cells treated once at -4 degrees C and those of freshly digested cells were similar to each other (26.3% vs 17.9%). The lowest blastocyst rates (5.88%) were observed when cells cryopreserved at -196 degrees C were used as donors. In experiment 3, the effect of different cell cycle synchronization methods on the in vitro development potential of pig NTEs was evaluated. The cleavage rate of NTEs derived from cycling cells was much better than that of NTEs derived from serum-starved cells (64.4% vs 50.5%, p < 0.05), but no significant difference was observed between the the blastocyst rates of the two groups. In experiment 4, the effect of different shapes of cultured fibroblast cells on the in vitro development of pig NTEs was examined. The fusion rate for couplets derived from rough cells was poorer than that observed in couplets derived from round smooth cells (47.8% vs 76.8%, p < 0.05). However, there were no significant differences observed in the cleavage rate and blastocyst rate. In conclusion, the present study indicated that (i) refrigerated pig GFP-transfected cells could be used as donors in nuclear transfer and these NTEs could be effectively developed to blastocyst stage; (ii) serum starvation of GFP-transfected cells is not required for preimplantation development of pig NTEs; and (iii) a rough surface of GFP-transfected donor cells affects fusion rate negatively but has no influence on the cleavage rate or blastocyst rate of pig NTEs.

Animals↗
PubMed1997

Combined effect of bacteriocin-producing lactic acid bacteria and lactoperoxidase system activation on Listeria monocytogenes in refrigerated raw milk.

The bactericidal activity of three bacteriocin-producing lactic acid bacteria alone and in combination with milk lactoperoxidase (LP) system activation against Listeria monocytogenes in refrigerated raw milk was studied. After 4 d at 4 degrees C, the population of L. monocytogenes in milk inoculated with bacteriocin-producing Lactococcus lactis subsp. lactis ATCC 11454, L. lactis subsp. lactis ESI 515 or Enterococcus faecalis INIA 4 was reduced by 0.21-0.24 log units. Activation of the LP system did not enhance inhibition at this temperature. After 4 d at 8 degrees C, L. monocytogenes levels in the non-activated LP system milk inoculated with L. lactis subsp. lactis ATCC 11454, L. lactis subsp. lactis ESI 515 or Ent. faecalis INIA 4 were reduced by 1.87, 1.54 and 1.11 log units compared to control milk, whereas in the activated LP system milk, this reduction was 1.99, 2.10 and 1.06, respectively. The higher nisin production by L. lactis subsp. lactis ESI 515 in milk with activated LP system than in non-activated LP system milk was responsible for the more pronounced decrease of L. monocytogenes counts in the former.

Animals↗
PubMed1998

Evaluation of bifidobacteria for the production of antimicrobial compounds and assessment of performance in cottage cheese at refrigeration temperature.

Twelve strains of bifidobacteria were identified which exhibited a broad spectrum of antagonistic activity against both Gram-positive and Gram-negative indicators, especially Pseudomonas species, using deferred antagonism spot plate assays. Inhibitory action was shown to be unrelated to hydrogen peroxide production and not solely dependent on acidity. However, attempts to detect inhibitory activity in cell-free supernatant fluids from these strains were unsuccessful. The production of inhibitory compound(s) by Bifidobacterium infantis NCFB 2255 was shown to be an unstable trait resulting in phenotypic alternation between production and non-production. Results from food trials using commercial cottage cheese which was inoculated with the inhibitor-producing strains of Bif. infantis NCFB 2255 and Bif. breve NCFB 2258 indicated that levels of Pseudomonas were reduced, but this observation was species-dependent. The viability of bifidobacteria themselves during storage in cottage cheese at refrigeration temperature was found to be a strain variable trait.

Antibiosis↗
PubMed1997

Stability of refrigerated and frozen solutions of tropisetron in either polyvinylchloride or polyolefin infusion bags.

OBJECTIVE: To investigate the stability of 50 microg/ml tropisetron in 0.9% sodium chloride or 5% dextrose injections on storage in either 100 ml polyvinylchloride (Tuliflex) or polyolefin (Clear-flex) infusion bags, at +4 degrees C and -20 degrees C. METHOD: A stability-indicating high-performance liquid chromatography (HPLC) assay was used to measure residual drug at day 0 (D0), D8, D15, D30, D60 and D90 for each bag. Samples were tested for pH at D0, D60 and D90. Frozen samples were thawed in a microwave oven according to a validated procedure before analysis. RESULTS: In 0.9% sodium chloride and 5% dextrose, no degradation products were observed in any of the chromatograms. No admixtures, at any time, contained less than 98.2% of the initial concentration. Only minor changes (-0.12 unit) in pH occurred over the storage period. No colour or other visual changes were seen in any sample. CONCLUSION: Tropisetron (50 microg/ml) in either 0.9% sodium chloride or 5% dextrose is chemically stable in polyvinylchloride or polyolefin bags for at least 3 months when stored in a refrigerator or in a frozen state.

Drug Stability↗
PubMed2006

Effect of dietary conjugated linoleic acid (CLA) on broiler performance, serum lipoprotein content, muscle fatty acid composition and meat quality during refrigerated storage.

1. A trial was conducted to investigate the effects of dietary conjugated linoleic acid (CLA) concentration on performance parameters, carcase composition, thiobarbituric acid reactive substances (TBARS) and fatty acid composition in leg and breast muscle and serum lipoprotein concentrations. 2. A total of 128 male chickens were allocated to 4 dietary treatments (0, 1, 2 and 3% CLA) and given a standard starter diet from d 1 to d 21 and a finisher diet from d 22 to d 42. Breast and leg muscles were stored at 4 degrees C for 1, 3 or 7 d. Fatty acid composition, TBARS and pH were determined in muscles. 3. Weight gain and feed conversion ratio were positively influenced by dietary CLA level. CLA isomer concentration in muscles increased linearly (P < 0.01) as dietary CLA increased. Addition of CLA to feeds significantly increased saturated fatty acid (SFA) and polyunsaturated fatty acid (PUFA) and decreased (P < 0.01) monounsaturated fatty acid (MUFA) in leg and breast tissues. 4. Muscle pH decreased with duration of refrigerated storage. TBARS values were significantly (P < 0.01) influenced by dietary CLA and storage time. CLA increased total cholesterol, LDL-cholesterol and HDL-cholesterol, but reduced triglycerides in the plasma of broilers.

Animal Feed↗
PubMed1994

The design of an emergency operating procedure in process control systems: a case study of a refrigeration system in an ammonia plant.

The purpose of this study was to develop a method to aid and support human operators in emergency operations. A conceptual model of system performance was constructed in order to observe the constraints of human capabilities under emergency conditions. Then the influence of emergent events and the applicable condition of procedural design principles were discussed. In order to help operators in handling the emergent event, a decision table support and a computer support were developed according to historical data and principles of procedural design. In order to verify the effects of above methods, a simulated experiment of handling the emergent event in the refrigeration system of an ammonia plant was performed. As shown by the experimental results, the support methods successfully improved the response speed of the subject, but did not improve accuracy. The results also revealed that the decision table support had a better effect on simple error type, whereas the 16-breadth computer support had a better effect on both the simple error type and complex error type.

Adult↗
PubMed1999

Refrigerated storage improves the stability of the complete blood cell count and automated differential.

A CBC count was performed on 113 random patient and 21 control specimens before and after 24-hour room temperature (RT) storage; 98 random patient and 20 control specimens also were analyzed before and after 24 hour 4 degrees C storage. The Cell-Dyn 3500 (Abbott Laboratories, Abbott Park, IL) was used for analysis. RT storage showed a decline in WBC count using the optical but not the impedance method, resulting in a large number of WBC flags. An increase in mean corpuscular volume also was seen for patient specimens. The automated WBC differential showed a decrease in the percentage of neutrophils and an increase in the percentage of lymphocytes, owing primarily to neutrophil degeneration. These changes also were seen in the manual differential to a similar degree. Storage of specimens at 4 degrees C largely prevented all of these changes. The implementation of refrigerated specimen storage is a simple, inexpensive method to improve the accuracy of CBC results for aged specimens on automated hematology analyzers.

Autoanalysis↗
PubMed1980

The stability of clinical chemistry specimens during refrigerated storage for 24 hours.

The authors investigated the stability of the tests comprising the SMA-6 and SMA-12 chemistry profiles during overnight refrigerated storage. Several constituents were found to undergo changes that were statistically significant when evaluated by a t test for paired comparisons. A recently published sequential method for judging sample stability was found to be somewhat less sensitive than the traditional statistical procedure. Only one determined value (CO2) underwent a change that was judged to be of medical significance. Two previously published criteria were used for this evaluation, one based on clinical judgment and the other on biologic variation. Variability of the results of repeat determination did not appear to be increased by overnight storage.

Blood Chemical Analysis↗