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PubMed2006

Evaluation of chemical and physical (high-pressure and temperature) treatments to improve the safety of minimally processed mung bean sprouts during refrigerated storage.

The objective of this study was to compare the effects of combined high hydrostatic pressure and temperature treatments with different chemical sanitation treatments (water, sodium hypochlorite, and hydrogen peroxide) on the microbiological properties of mung bean sprouts. In a first study, the raw product was subjected to several combined high-pressure and temperature treatments for calculating a mathematical model by a response surface methodology. The number of pressure-temperature (150 to 400 MPa; 20 to 40 degrees C) combinations was limited to 10. In addition, a model system consisting of mung bean sprout juice was inoculated with Listeria monocytogenes (CECT 4032). Microbial inactivation with this model system was also investigated by a response surface methodology. The highest aerobic mesophilic bacteria and L. monocytogenes inactivation was achieved at maximum pressure and temperature (5.5 and 1.8 log cycles, respectively). In a second study, the effect of five different processing lines on the microbial load reduction of minimally processed mung bean sprouts during refrigerated storage was studied. All treatments reduced the initial population of aerobic mesophilic bacteria and fecal coliforms, with the physical treatment of 400 MPa and 40 degrees C being the most effective, showing initial reductions of 5.8 and 7.8 log CFU/ g, respectively. Recovery of bacteria from sprouts treated under these conditions was not observed during storage. However, the sprouts that received washing treatments with water, sodium hypochlorite, and hydrogen peroxide exhibited increases in aerobic mesophilic and fecal coliform counts after 3 days of storage at 4 degrees C.

Anti-Infective Agents, Local↗
PubMed2006

Leuconostoc carnosum associated with spoilage of refrigerated whole cooked hams in Greece.

A polyphasic taxonomic approach was used to identify a major atypical group of gas-forming, arginine-negative lactic acid bacteria associated with spoilage of whole (nonsliced) refrigerated (4 degrees C) cooked hams produced in two Greek industrial meat plants. Biochemical characterization revealed that the ham isolates shared their phenotypic properties with Leuconostoc carnosum, Weissella viridescens, and Weissella hellenica. However, gas chromatographic analysis of cellular fatty acids clearly differentiated the ham isolates from the Weissella spp. None of the isolates contained eicosenoic acid (n-C20:1), which is typically synthesized by W. viridescens, but all strains contained high amounts of C 19cycl acid, which is absent in W. hellenica and has been found in trace amounts in W. viridescens. All strains had similar cellular fatty acid profiles, which were qualitatively similar to those of the cellular fatty acids of L. carnosum. In addition to the phenotypic and chemotaxonomic tests, three representative isolates were studied using a lactic acid bacteria database, which employs 16S and 23S HindIII restriction fragment length polymorphism patterns as operational taxonomic units in a numerical analysis. The isolate patterns were identical to those of the L. carnosum type strain, NCFB 2776T. Based on the polyphasic taxonomic approach, the dominating lactic acid bacteria group was identified as L. carnosum.

Aldehyde-Lyases↗
PubMedDate not supplied

[Verification of the proteolytic and lipolytic activities of the microbial flora isolated from raw, refrigerated, type B milk. II. Psychrotrophic microorganisms].

The aim of this work was to evaluate the microbiological quality of raw type B milk, kept under refrigeration at 3 degrees C, for a period of 15 days. The milk was enumerated and isolated a total of 180 microorganisms, of which 80 were psychrotrophics. The ability of these microorganisms to produce lipolysis and/or proteolysis in the milk was evaluated. Concerning the microbiological analysis, the samples analyzed presented high values for total counting. The results from the initial counting were 2.7 x 10(4) UFC/ml for psychrotrophic, with a predominance of Gram negative bacilli, which were highly lipolytic and had proteolytic activities associated.

Animals↗
PubMedDate not supplied

Effects of a refrigerated amalgam bonding system on fracture resistance.

This in vitro study evaluated the effectiveness of using an amalgam bonding system at refrigerated temperature to regain fracture resistance in molars with large mesial-occlusal-distal restorations. Nineteen pairs of homologous contralateral pairs of third molars were used, with control teeth remaining intact. Although the bonded amalgam group developed 81% of the fracture strength values of the intact teeth, the intact teeth were found to have significantly higher fracture strength values (p = 0.0326, paired t-test).

Dental Amalgam↗
PubMed2006

[Reconstructive vascular surgery with long-term refrigerated homografts].

In most cases of vascular repair a graft implantation is needed. Homografts have been proven to be suitable conduits when no autogenous graft is available. High viability index of vein homograft was confirmed during long term refrigerated storage in tissue culture medium, however there was no data of successful implanted cases. We report two cases of great saphenous vein (GSV) homograft implantation with excellent early results. In the first case graft-popliteal bypass was performed with vein homograft after septic ilio-femoral Dacron graft explantation and aorto-bifemoral Silver bypass procedure. Septic crossover synthetic bypass was replaced with GSV homograft in the second case. Long term storage of vein allografts at 4 C is a valuable and cost-effective option for revascularization and we propose wide-scale introduction of this method.

Aged↗
PubMed1972

Methods for dissecting dry insects and insects preserved in fixative solutions or by refrigeration.

The methods described in this paper for the dissection of dry and preserved insects have been used for several years on various species, mainly mosquitos. In the past, dry or partially dry mosquitos found in traps or in the laboratory had to be discarded. By softening these insects in a detergent solution, however, it is possible to make most observations in the same way as on fresh material. The preservation of insects in the dry state, in a fixative, or in the refrigerator after collection enables much larger samples to be studied; the whole of the material can be examined and the work can be done when time permits. In addition, material can be sent to central laboratories far from the place of collection, and infected insects can be kept in stock for teaching purposes.

Animals↗
PubMed1993

Factors affecting spoilage microflora succession on lamb carcasses at refrigeration temperatures.

Three bacterial groups were detected during the shelf-life of lamb carcasses stored at refrigeration temperatures: coryneforms (mostly Brochothrix thermosphacta), Gram-positive cocci (staphylococci) and Gram-negative bacilli (Pseudomonas spp. and Moraxella spp.). Influence of categorical variables such as sampling day, sampling area and sampling method on their recovery was analysed by a chi-square test of independence and loglinear analysis. Hierarchical loglinear modelling proved to be very useful as several three-way interactions of factors were observed.

Actinomycetales↗
PubMed1989

[Materials properties of zinc phosphate cements after delayed setting on refrigerated slabs].

Two of the zinc phosphate cements commonly used in orthodontics were mixed, with special attention being paid to the longest possible working time, and examined by scientific methods. The results showed that mixing should generally be carried out on frozen slabs (-18 degrees C to -24 degrees C) and for not longer than 5 min. If a maximum compressive strength is required, mixing should be done at refrigerator temperature (+4 degrees C to +8 degrees C) for no more than 1.5 min by accepting a shorter working time. Neither cement shows any notable physicochemical differences, as regards the material.

Chemical Phenomena↗
PubMed1988

Development of a passive device for freezing large amounts of transplantable skin at one time in a -70 degrees C mechanical refrigerator.

A simple device has been developed for the simultaneous cooling of up to 9120 cm2 of allograft skin in a flat package format. The device, named an insulated alternating-offset heat sink device, is composed of a stack of interleaved layers of 2.0-mm-thick packets of skin and 3.18-mm-thick aluminum heat sinks (each 33.0 cm long by 22.9 cm wide). Four skin packets are placed in a single layer on each heat sink plate, and the number of plates can be varied to accommodate different numbers of skin packets. Every heat sink protrudes 6.3 cm of its 33.0-cm length beyond the skin packets to make a fin for heat convection, but adjacent plates alternate the direction of their fin protrusion so that the layers of plates alternate in their 6.3-cm offset. Insulation layers of 2.54-cm-thick expanded polystyrene are placed on the exposed surfaces of the top and bottom heat sinks in the stack, and the stack is held together by rubber bands. The device is cooled in a -70 degrees C mechanical refrigerator. Maximal cooling rates of -1.8 degrees C min-1 are obtained for both 6- and 11-plate devices, and -3.0 degrees C min-1 for a 2-plate device. The exothermic temperature plateaus associated with skin cooled in these devices are 1.5-1.8 min in duration. Skin cooled by this technique maintains levels of glucose oxidation similar to those associated with skin cooled by liquid nitrogen vapor at a controlled rate of -1 degree C min-1, provided rapid warming is employed after -70 degrees C storage. The development of this device provides a method for the simple, low-cost cryopreservation of the large amounts of allograft skin obtained from a cadaveric donor.

Cell Survival↗
PubMed1990

Survival and infectivity of Trypanosoma brucei in refrigerated pig blood.

Trypanosoma brucei parasites survived for 72 h or longer in refrigerated pig blood. The survival period was directly proportional to the initial parasite concentration of the sample. Infectivity of the parasites declined faster than survival, being less than 1 per 10(5) motile organisms at 72 h. The stage of infection in the pig (early vs. late) did not appear to influence subsequent survival periods or infectivity of the parasites in vitro.

Animals↗
PubMed2004

Viability of vaginal probiotic lactobacilli during refrigerated and frozen storage.

The viability of six different strains of probiotic vaginal Lactobacillus was examined in two different cryoprotective media, during refrigerated versus frozen storage, and using two traditional types of stock cultures for starting the biomass production. Freezing at -20 degrees C and -70 degrees C had much less adverse effect on viability than did storage at 7 degrees C, and the reduction in viability was greater at -20 degrees C than at -70 degrees C. The strains showed variation in the extent of the viability losses during both types of storage. Milk-yeast extract (MYE) was shown to be the more suitable protective medium to maintain viability of the strains during the storage. The vaginal Lactobacillus strains are most stable in MYE at -70 degrees C with only a small decrease of the viability observed under these conditions. The viable cell counts of Lactobacillus paracasei CRL 1251 and CRL 1289, L. crispatus CRL 1266 and L. salivarius CRL 1328 remained around 1 x 10(8) CFU/mL after 24 months of storage at -70 degrees C, or up to 18 months for L. acidophilus CRL 1259.

Journal Article↗
PubMed2005

Inhibitory effects of microencapsulated allyl isothiocyanate (AIT) against Escherichia coli O157:H7 in refrigerated, nitrogen packed, finely chopped beef.

Allyl isothiocyanate (AIT) is an effective inhibitor of various pathogens, but its use in the food industry is limited by its volatility and pungency. The objective of this study was to overcome the volatility of AIT by microencapsulation and evaluate its antimicrobial effectiveness against Escherichia coli O157:H7 in chopped beef. Chopped beef was aseptically prepared and inoculated with a five-strain cocktail of E. coli O157:H7 to yield 4 or 8 log10 cfu/g. AIT was microencapsulated in gum acacia to yield 3.7-54.8 mg AIT/g at a ratio of 1:4 and freeze dried. Microcapsules at 5% or 10% (w/w) were then added to experimental samples that were packed under nitrogen, and stored at 4 degrees C for 18 days. Samples were analyzed for numbers of E. coli O157:H7 and the aerobic mesophilic bacteria (TAC) at 3-day intervals. AIT at 4980 ppm eliminated both low and high levels of inoculated E. coli O157:H7 after 15 and 18 days of storage, respectively. AIT at 2828 ppm reduced E. coli by 2.7 log10 cfu/g by 18 days of storage. AIT levels <1000 ppm were not more effective in reducing E. coli survival than the control treatment without AIT addition. AIT at 170-1480 ppm had negligible effects on the TAC, and while 4980 ppm kept TAC levels <or=3 log10 cfu/g during 18 days of storage, the TAC reached 7.25 log10 cfu/g in the control. It was found that AIT microencapsulated in gum acacia could be used in chopped refrigerated beef to reduce or eliminate large numbers of E. coli O157:H7.

Animals↗
PubMed2004

Birth of mice after in vitro fertilization using C57BL/6 sperm transported within epididymides at refrigerated temperatures.

The transportation of cryopreserved spermatozoa is an economical, efficient, and safe method for the distribution of mouse strains from one facility to another. However, spermatozoa from some strains, including C57BL/6 (B6), are very sensitive to freezing and thawing and frequently fail to fertilize eggs by conventional in vitro fertilization methods at the recipient mouse facility. Since many genetically engineered mice have the B6 genetic background, this sensitivity poses a major obstacle to studies of mouse genetics. We investigated the feasibility of transporting spermatozoa within epididymides under non-freezing conditions. First, we examined the interval that B6 and B6D2F1 (BDF1) spermatozoa retained their ability to fertilize when stored within epididymides at low temperatures (5 degrees C or 7 degrees C). Fertilization rates were >50%, irrespective of the spermatozoa used, when epididymides were stored for 3d at 7 degrees C. B6 spermatozoa, but not BDF1 sperm, had better retention of fertilizing ability at 7 degrees C versus 5 degrees C. We then transported freshly collected B6 and BDF1 epididymides from a sender colony to a recipient colony using a common package delivery service, during which the temperature was maintained at 5 degrees C or 7 degrees C for 2d. Sufficiently high fertilization rates (68.0-77.5%) were obtained for all experimental groups, except for B6 spermatozoa transported at 5 degrees C. These spermatozoa were successfully cryopreserved at the recipient facility and, yielded post-thaw fertilization rates of 27.6-66.4%. When embryos derived from the B6 spermatozoa that were transported at 7 degrees C were transferred into recipient females, 52.7% (38/72) developed to term. In conclusion, transportation of epididymides at refrigerated temperatures is a practical method for the exchange of mouse genetic resources between facilities, especially when these facilities do not specialize in sperm cryopreservation. For the B6 mouse strain, the transportation of epididymides at 7 degrees C rather than 5 degrees C, is recommended.

Animals↗
PubMed2006

Synesthetic colors determined by having colored refrigerator magnets in childhood.

Synesthesia is a condition in which percepts in one modality reliably elicit secondary perceptions in the same or a different modality that are not in the stimulus. In a common manifestation, synesthetes see colors in response to spoken or written letters, words and numbers. In this paper we demonstrate that the particular colors seen by a grapheme-color synesthete AED were learned from a set of refrigerator magnets and that the synesthesia later transferred to Cyrillic in a systematic way, with the colors induced by the Cyrillic letters determined by their visual or phonetic similarity to English letters. Closer examination of the data reveals that letters of either language that are more visually similar to the English capitals in the magnet set are also more saturated. In order to differentiate AED's synesthesia from ordinary memory, we use a novel psychophysical method to show that AED's synesthetic colors are subject to ordinary lightness constancy mechanisms. This suggests that the level of representation at which her synesthesia arises is early in the stream of visual processing.

Adult↗
PubMed1978

Feulgen hydrolysis at refrigerator temperature.

In order to search for the better FEULGEN hydrolysis conditions, the 2 kinds of hydrolysis with 5 N HCl - at room temperature and at refrigerator temperature - were comparatively studied on rat liver imprints. 2 reactions were used: with the SCHIFF reagent binding to aldehyde groups and with methylene blue staining phosphate groups of DNA. Cytophotometry was coupled with morphological examination of stained nuclei. It was found that 1. cold hydrolysis has no substantial advantage when revealing DNA with the SCHIFF reagent but 2. it has undoubtful profit to reveal DNA, and in particular its acid-labile fraction, when staining with methylene blue. With the cold hydrolysis-methylene blue technique at least 3 categories of DNA with different acid-lability can be revealed and characterized morphologically in rat liver nuclei.

Animals↗
PubMed1997

Refrigerated storage and cryopreservation of black drum (Pogonias cromis) spermatozoa.

Procedures were developed for the collection, refrigerated storage and cryopreservation of black drum spermatozoa. Sperm samples were collected by removing and slicing the testis, and suspending the spermatozoa in Hanks' balanced salt solution (HBSS) at 200 mOsm/kg. Threshold activation (10%) of black drum spermatozoa occurred at 370 mOsm/kg, and complete activation occurred at 580 mOsm/kg in HBSS. Sperm cells activated in artificial seawater had higher motility than those activated in HBSS at osmolalities from 350 to 500 mOsm/kg. Spermatozoa stored at 4 degrees C in HBSS or artificial seawater at osmolalities from 202 to 290 mOsm/kg retained motility longer than did those stored at other osmolalities Dilution rate had no effect on sperm storage time at 4 degrees C. Four chemicals were evaluated as cryoprotectants: dimethyl sulfoxide (DMSO), n,n-dimethyl acetamide (DMA), methanol, and glycerol. Glycerol and DMA at concentrations of 10% significantly reduced motility within 52 min. Spermatozoa were cryopreserved at 3 freezing rates (-27, -30, or -45 degrees C/min) in a nitrogen vapor shipping dewar or a computer-controlled freezer. Spermatozoa frozen using 10% DMSO had the highest post-thaw motility at a freezing rate of -27 or -30 degrees C/min. Spermatozoa frozen using 5% glycerol, 5% DMSO, or 10% DMSO had the highest post-thaw motility at a freezing rate of -45 degrees C/min.

Journal Article↗
PubMed1997

Minimum growth temperatures of Hafnia alvei and other Enterobacteriaceae isolated from refrigerated meat determined with a temperature gradient incubator.

Minimum growth temperatures of Hafnia alvei (n = 156) and other Enterobacteriaceae isolates (n = 162) from refrigerated meat samples (n = 88) and control strains of H. alvei (n = 81) from clinical and environmental samples were determined with a plate-type continuous temperature gradient incubator on nutrient agar. The dominant species, Hafnia alvei and Serratia liquefaciens had mean minimum growth temperatures of 2.6 (range, 0.2-3.7 degrees C) and 1.7 (range, 0.2-2.6 degrees C), respectively. Values for other species included: Enterobacter agglomerans, 1.3 (0.7-1.7 degrees C); Escherichia coli, 8.7 (8.4-8.9); Escherichia vulneris, 1.6 (0.8-2.6 degrees C); and Serratia fonticola, 2.0 (1.1-3.0 degrees C). The H. alvei reference strains did not differ markedly from the meat isolates, with the exception of the diarrhoeagenic eae A positive strains (10.6, 10.2-11.5 degrees C). The representatives of H. alvei hybridization groups (HG) 1 and 2 did not differ in their minimum growth temperatures. The observed heterogeneity of the minimum growth temperatures of many Enterobacteriaceae species may be explained by limitations of the systems used for identification of enterobacteria, inadequacy of the Enterobacteriaceae taxonomy or true growth temperature heterogeneity within the various species.

Animals↗