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  • 1
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary Blended 9-day-old mycelia of Aspergillus parasiticus NRRL 2999 were tested for their ability to degrade aflatoxins B1 and G1 at 7,19,28,36, and 45°C. Rates for degradation of aflatoxin B1 and G1 were maximum at 28°C. Intermediate rates of aflatoxin degradation were observed at 19 and 36°C while little aflatoxin was degraded at 7 and 45°C. Five different pH values (2.0, 3.0, 4.0, 5.0, and 6.5) were also tested to determine the effect of pH on ability of blended 9-day-old mycelia of A. parasiticus NRRL 2999 to degrade aflatoxins. The ability of mycelia to degrade aflatoxin was pH-dependent. Of the pH values tested, greatest rates of aflatoxin B1 and G1 degradation occurred when pH was in the range of 5 to 6.5. Little aflatoxin was degraded at pH 4.0 and essentially no aflatoxin was degraded by mycelia at pH 2.0 or 3.0 although some aflatoxin was degraded by acid conditions only at pH values of 4 or less.
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  • 2
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary This study determined how processing in cook/chill foodservice systems affected the quantity of sublethally injured bacteria in food. Beef loaf and frozen green beans were each prepared three times in a laboratory simulation following time-temperature recommendations of the Hazard Analysis Critical Control Point model. Beef loaf (15 kg) was initially cooked (1 kg/loaf) to a mean and temperature of 66°C; stored 24 h at 6°C and sliced, 100 g/poriton. Beans (4.5 kg) were removed from the freezer, stored 24 h at 6°C, and portioned, 100 g/ portion. Portions were helds at 6°C for 2 h and then were microwave-heated individually for 20, 50, 80, or 110s. Samples were then plated using Plate Count Agar (PCA) to obtain aerobic plate count (APC) and PAC plus 3.0% (beans) or 4.5% (beaf loaf) sodium chloride. The difference in results between the two counts (APC less PCA + NaCl) was defined as a measure of sublethally injured bacteria in the sample. The proportion of injured cells in beef loaf before microwave-heating was larger than that in green beans before microwave-heating probably because the beef loaf was initially cooked. Lenghtening the time of microwave-heating increased the proportion of injured cells in all microwave treatments of beef loaf and also in green beans when the time was 50 or more seconds.
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  • 3
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary Extracts of 9-day-old mycelia of Aspergillus parasiticus NRRL 2999 were assayed for peroxidase activity and for their ability to degrade aflatoxin. A positive relationship existed between rates of aflatoxin degradation and amount of peroxidase activity in these extracts. The supernatant fluid of homogenates from mycelia grown under similar conditions varied in amount of peroxidase present (170 to 2215 U/g). The fraction obtained, by precipitation with (NH4)2SO4 at 45% of saturation, from six different homogenates prepared from three mycelial mats contained peroxidase and degraded aflatoxin. Rates of aflatoxin degradation by and amounts of peroxidase activity in each sample obtained from mycelial homogenates with (NH4)2SO4 at 60% of saturation varied; however, when increased amounts of peroxidase activity were present, more aflatoxin was degraded and vice versa. Relatively little peroxidase activity was present in the fraction obtained with (NH4)2SO4 at 30% of saturation and little or no aflatoxin was degraded by this precipitate. Trends for degradation of aflatoxin when more or less peroxidase activity was present in mycelial preparations suggest that the enzyme may be involved in degradation of aflatoxin by the Aspergillus.
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  • 4
    ISSN: 1432-0738
    Keywords: Aflatoxin ; Aflatoxin excretion ; Mycotoxin ; Mink ; Feces ; Urine ; Aflatoxin ; Aflatoxin-Ausscheidung ; Mykotoxin ; Nerz ; Kot ; Urin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung An Nerzen (Mustela vison) wurde die Ausscheidung von Radioaktivität während 7 Tagen nach intraperitonealer Injektion zweier verschieden hoher Dosen von markiertem Aflatoxin B1 untersucht. Männliche Tiere, die eine einmalige Dosis von 25 μg Aflatoxin B1 pro kg Körpergewicht erhielten, schieden im Durchschnitt 89,5% der verabreichten Radioaktivität aus (56,8% im Kot, 32,7% im Urin), während weibliche Tiere in der Zeitspanne von sieben Tagen im Durchschnitt 85% der verabreichten Radioaktivität ausschieden (63,6% im Kot, 21,4% im Urin). Männliche und weibliche Tiere, die 150 μg Aflatoxin B1 pro kg Körpergewicht erhielten, schieden während der sieben Tage nach der Behandlung mit dem Toxin durchschnittlich 76,9–80,1% der verabreichten Radioaktivität aus. Diese Tiere schieden im Urin etwas mehr Radioaktivität aus als Tiere, die eine niedrigere Dosis Aflatoxin erhalten hatten (37,2 gegenüber 32,7% bei männlichen, 32,7 gegenüber 21,4% bei weiblichen Tieren). Der größte Teil der letztlich im Kot oder Urin ausgeschiedenen Radioaktivität zeigte sich unabhängig von Geschlecht und Dosierung innerhalb der ersten 24 Std nach Applikation des Toxins.
    Notes: Abstract Excretion of radioactivity by mink (Mustela vison) during 7 days after intraperitoneal injection of two different amounts of aflatoxin B1 was studied. Male mink that received a single dose of 25 μg aflatoxin B1/kg body weight excreted an average of 89.5% of administered radioactivity (56.8% via feces, 32.7% via urine); whereas female mink excreted an average of 85% (63.6% via feces, 21.4% via urine) of administered radioactivity during the 7-day period. Male and female mink given 150 μg aflatoxin B1/kg body weight excreted an average of 76.9–80.1% of administered radioactivity during the 7 days that followed treatment with toxin. These mink excreted somewhat more of the administered radioactivity in their urine than did the mink that received the lower dose of aflatoxin (37.2 vs. 32.7% for males and 32.7 vs. 21.4% for females). Regardless of sex and dosage of toxin, most of the radioactivity ultimately excreted either through feces or urine appeared in the first 24 h after toxin was administered to mink.
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  • 5
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Staphylococcus aureus was inoculated into uncooked mixtures of ground beef and soy protein and survival of the organism was determined during the stages of food handling that would occur in a hospital with a chill foodservice system. Although the initial inoculum was only approximately 5000/g, heating the mixture as loaves in a convection oven at 121°C to an internal temperature of 60°C was not lethal to S. aureus. Numbers of S. aureus in loaves decreased during holding at 5°C for 24, 48 and 72 hr. Numbers of S. aureus in the center of the final product were less than 3/g after loaves were portioned, held chilled at 5°C for 2 hr, and portions heated to 80°C in a microwave oven.
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  • 6
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Preparation and service of food as practiced in hospital chill food-service systems were simulated. Beef-soy loaves, containing 25% rehydrated textured soy crumbles and 75% ground beef, were baked to 60°C in a convection oven operating at 121 ± 8°C; stored chilled at 5 ± 3°C for 24, 48 or 72 hr; portioned; held chilled at 5 ± 1°C for 2 hr, and then heated in a microwave oven for 55 set to achieve an internal temperature of 80°C just before the products were evaluated by a consumer panel. Overall acceptability scores for the final product were almost identical, regardless of the length of chilled storage at 5 ± 3°C. Viable bacteria remained in the center of product after the loaves were heated to 60°C, stored at 5 ± 3°C for 24–72 hr, portioned, held chilled at 5 ± 1°C for 2 hr, and portions heated to 80°C.
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  • 7
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 37 (1972), S. 0 
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Dichlorodifluoromethane (f-12) can effectively and irreversibly inhibit the catalytic activity of o-diphenol oxidase (tyrosinase, polyphenol oxidase) in a simple buffered system. The degree of inhibition was influenced by concentration of and duration of exposure to f-12 and by time and vigor of agitation. Under the conditions tested, maximum inhibition of o-diphenol oxidase was obtained using 2.9 mole % f-12 and agitating samples at room temperature and 180 cpm for 20–40 min.
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  • 8
    ISSN: 1573-0832
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract A sterile glucose-mineral salts broth was fortified with equimolar concentrations (10-3 M) of various organic acids and intermediates in the tricarboxylic acid cycle. Appropriate media were neutralized with 2 N NaOH, inoculated with spore suspensions or mycelial pellets ofPenicillium rubrum and incubated quiescently for 14 days or with shaking for 5 days. Rubratoxins were recovered from culture filtrates by ether extraction and resolved by thin-layer chromatography. Toxin formation in quiescent cultures was enhanced by malonate but was not markedly affected by ethyl malonate, shikimate, and acetate or by isocitrate or oxaloacetate added in the presence of malonate. Citrate, cis-aconitate, α-ketoglutarate, succinate, fumarate, and malonate when present in the medium alone or in conjunction with malonate caused a 15 to 50% reduction in rubratoxin formation. Acetyl-CoA (10-5 M/flask) caused an 80% increase in toxin yield. Rubratoxin formation in shake cultures was not affected by succinate and malonate. All other combinations of intermediates and malonate caused a 10 to 50% reduction in toxin formation. At 10−3 M, citrate enhanced rubratoxin B formation and stimulated rubratoxin A production by as much as 100%. Above 10−3 M, citrate inhibited toxin production. Incorporation of [2-14C]acetate into rubratoxin was enhanced by malonate, fumarate, and malonate. A combination of pyruvate and malonate produced a 40% increase in [2-14C]acetate incorporation into rubratoxin. The highest reduction of labeled acetate incorporation (36%) was caused by succinate or α-ketoglutarate combined with malonate.
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  • 9
    ISSN: 1573-0832
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The ability of 9-day-old mycelia of Aspergillus parasiticus NRRL 2999 to degrade aflatoxin varied depending on the substrate used to grow the mold. Substrates which allowed substantial mycelial growth yielded mycelia which actively degraded aflatoxin. Substrates which allowed minimal growth of mycelia yielded mycelia with little ability to degrade aflatoxin. Biodegradation of aflatoxin was also strain-dependent. A. parasiticus NRRL 2999 and NRRL 3000 actively degraded aflatoxin, A. flavus NRRL 3353 was less active, and A. flavus NRRL 482 and A. parasiticus NRRL 3315 degraded minimal amounts of aflatoxins. Those aspergilli producing greatest amounts of aflatoxin also degraded aflatoxins most rapidly, whereas those strains which produced minimal amounts of aflatoxin generally degraded aflatoxins less effectively. Substrates which allowed maximum aflatoxin production also yielded mycelia which actively degraded aflatoxins, whereas media which allowed limited production of aflatoxin generally yielded mycelia with minimal ability to degrade the toxin. Although exceptions exist, generally as aflatoxin production increased so did the ability of mycelia to degrade the toxin.
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  • 10
    ISSN: 1573-0832
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Steaming one-half of a lot of 9-day-old mycelia of Aspergillus parasiticus NRRL 2999 for 6 min resulted in little or no subsequent degradation of aflatoxin B1 or G1 by these mycelia. The other half of these mycelia was not heat-treated and degraded aflatoxins B1 and G1 Filtrates of the growth substrate which remained after the mycelium was removed from 8- to 15-day old cultures of A. parasiticus NRRL 2999 did not degrade substantial amounts of aflatoxin B1 or G1, whereas mycelia originally produced on these filtrates degraded substantial amounts of both aflatoxins. The supernatant fluid from homogenates of 9-day-old mycelia of A. parasiticus NRRL 2999 degraded aflatoxins B1 and G1 when 0.1 M or 1.0 M phosphate buffer, pH 6.5, was used to suspend the homogenate. These data support the hypothesis that the aflatoxin degrading factor(s) present in the mycelium of A. purasiticus is/are enzyme(s) or at least influenced by enzyme(s).
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