共查询到20条相似文献,搜索用时 31 毫秒
1.
Hemisuccinate (HS) and hemiglutarate (HG) of aflatoxin B2a (afla B2a ) were prepared by refluxing afla B2a with the corresponding anhydride and 4-N, N-dimethylaminopyridine in tetrahydrofuran. Two epimers of the respective HS or HG which show different chromatographic behavior and physiochemical properties were isolated and characterized. Afla B2a -HS hydrolyzes very rapidly in aqueous solution and was not used for further study. Afla B2a -HG hydrolyzes at a much slower rate and was selected for the coupling to protein. Using the mixed anhydride method, as much as 12 moles of afla B2a -HG were conjugated to each mole of bovine serum albumin (BSA). The antibody obtained from rabbits immunized with afla B2a -HG BSA is most specific to afla B1 and shows little cross reaction with afla G1 and aflatoxicol. The lower limit for detection of afla B1 by radioimmunoassay using this antibody is in the range of 30–50 pg per assay. 相似文献
2.
Cavit Bircan Sheryl A. Barringer Ulku Ulken & Rahsan Pehlivan 《International Journal of Food Science & Technology》2008,43(8):1492-1498
Three hundred and thirteen of 2643 dried fig, two of eighty hazelnut, sixteen of twenty-eight pistachio, five of ten peanut and nineteen of twenty-three paprika samples for export from Turkey were contaminated with total aflatoxins in the range of 0.2–162.76, 5.46–6.55, 2.31–63.11, 0.75–26.36 and 1.79–6.55 μg kg−1 , respectively. Samples were collected from January to August 2007 and tested for aflatoxins (B1 , B2 , G1 and G2 ) by immunoaffinity column extraction using RP-HPLC. Fifty-six of the 313 dried fig, all of the contaminated hazelnut and pistachio, two of the sixteen peanut and three of the nineteen paprika samples exceeded the regulatory limits of the European Union. The ratio of the different types of aflatoxin present in each sample exhibited great variability. For example, of 313 contaminated fig samples, 159 contained only aflatoxin B1 , eighty-five contained B1 (49.7%) + G1 (50.3%), twenty-two contained only G1 , twenty contained B1 (89.4%) + B2 (10.6%), thirteen contained B1 (73.7%) + B2 (10.8%) + G1 (15.5%) and fourteen contained all four types, B1 (26%) + B2 (2.5%) + G1 (66.5%) + G2 (5%). 相似文献
3.
Ten samples of fennel seed from fields in India were examined for the presence ofaflatoxins B1 , B2 , G1 and G2 . Five of the samples were fluorescent or became fluorescent during a 12 month storage period. Only aflatoxins B1 , B2 and G1 were identified. One nonfluorescent sample contained detectable aflatoxin B1 after 12 months of storage. 相似文献
4.
Mycelial growth and toxin production by Asperigillus parasiticus were inhibited by garlic concentrations of 0.3–0.4%. When the fungus was grown in broth, aflatoxin B1 production was inhibited at a garlic concentration of 0.3% while aflatoxin G1 production was inhibited by 0.25% garlic. When growth on rice, aflatoxin B1 was detected at garlic concentrations of up to 2.5%. Aflatoxin G1 was detected at 1.25% garlic concentration but not above this level. 相似文献
5.
Dried figs are sensitive commodities to aflatoxin contamination. Although preventive methods are the logical solution to aflatoxin problems, once the product is contaminated, decontamination procedures are inevitable. In this study, the effectiveness of a procedure consisted of acidification/alkalization, and heat treatment in degradation of aflatoxins was evaluated. The pH of dried fig extracts was adjusted to 3.1, 3.5, 6, 8 or 10 by adding acid or base. Extracts were heated at 50, 75 or 98C for 1 or 2 h, and then the residual aflatoxin B1 , B2 , G1 and G2 were determined. The highest level of degradation for aflatoxin B1 (97 ± 1%) and B2 (87 ± 1%) were observed at pH 10 in samples heated at 98 and 50C, respectively. Some treatments resulted in 100% degradation of aflatoxin G1 and G2 so that they could not be detected.
Aflatoxin contamination is a serious problem for a number of processed and non-processed foods, including dried figs. This not only presents severe risks to human and animal health but also causes economic problems for countries such as Turkey, U.S.A., Greece and Spain, which produce and export dried figs. It is clear that detoxifying studies are unavoidable when the amount of crop contaminated by toxins is considered. Therefore, the food industry is in search of applications that are effective in mycotoxin detoxification and adaptable to food processes. This is the first report on degradation of aflatoxins in naturally contaminated dried figs by such a promising method. 相似文献
PRACTICAL APPLICATIONS
Aflatoxin contamination is a serious problem for a number of processed and non-processed foods, including dried figs. This not only presents severe risks to human and animal health but also causes economic problems for countries such as Turkey, U.S.A., Greece and Spain, which produce and export dried figs. It is clear that detoxifying studies are unavoidable when the amount of crop contaminated by toxins is considered. Therefore, the food industry is in search of applications that are effective in mycotoxin detoxification and adaptable to food processes. This is the first report on degradation of aflatoxins in naturally contaminated dried figs by such a promising method. 相似文献
6.
The effect of γ-irradiation for controlling the production of aflatoxin B1 by Aspergillus flavus in ground beef stored at 5C for 2 weeks was investigated. Aspergillus, Penicillium, Cladosporium, Mucor, Scopulariopsis, Candida and Rhodotorula were the most common fungal genera contaminating ground beef. A. flavus and A. niger were the most common Aspergillus spp. Aspergillus flavus isolates were able to produce aflatoxin B1 in ground beef. Only 3 (20%) samples of ground beef were contaminated with aflatoxin B1 (25–45 μg/Kg). Gamma irradiation dose levels resulted in an immediate reduction in the total numbers of A. flavus. No growth or aflatoxin B1 production occurred at 1.50 kGy during storage. 相似文献
7.
ABSTRACT: Aqueous extract of ajowan seeds was found to contain an aflatoxin inactivation factor (IF). Thin layer chromatography analysis of the toxins after treatment with IF showed relative reduction of aflatoxin G1 > G2 > B1 > B2 . Quantification of toxin using a fluorotoxin meter as well as the Enzyme Linked Immuno s orb ent Assay (ELISA) confirmed these findings. An approximate 80% reduction in total aflatoxin content over the controls was observed. This observed phenomenon of reduction in total toxin was referred to as toxin inactivation. Temperature was found to influence the rate of toxin inactivation. At 45 °C, it was found to be rapid during the initial 5 h and slowed later. The IF was found to retain considerable activity even after boiling and autoclaving, indicating partial heat stability. The activity was lost below pH 4.0. Above pH 4.0, it increased gradually, reaching the maximum at pH 10.0. IF was found to be stable to gamma irradiation. Toxin decontamination in spiked corn samples could be achieved using IF. This study emphasizes the potential of ajowan IF in aflatoxin removal from contaminated food commodities. However, the biological toxicity, if any, of the IF inactivated aflatoxins needs to be confirmed, and the work in this direction is in progress. 相似文献
8.
The synergistic bactericidal effects of vitamin B1 (thiamine dilauryl sulfate) and the efficacy of commercial sanitizers for minimization of Bacillus cereus contamination in cooked rice were investigated. Sanitizer-treated rice exhibited a greater reduction than water-treated rice, while sanitizer-treated rice with Vitamin B1 produced an even greater reduction. The treatments for B. cereus in rice included (1) 100 ppm hydrogen peroxide with 500 ppm vitamin B1 ; (2) 200 ppm hydrogen peroxide with 100 ppm vitamin B1 ; (3) 400 ppm hydrogen peroxide; (4) 50 ppm chlorine with 500 ppm vitamin B1 ; (5) 60 ppm chlorine with 300 ppm vitamin B1 ; (6) 70 ppm chlorine with 100 ppm vitamin B1 ; (7) 80 ppm chlorine; and (8) 100,000 ppm ethanol with 500 vitamin B1. All treatments completely eliminated B. cereus in rice. The sensory properties of all sanitizer-treated cooked rice did not differ significantly from the same properties for water-treated cooked rice.
The prevalence of Bacillus cereus in rice and rice products has been documented and control of the growth of B. cereus in rice is an important consideration. The results obtained from this study can be of use to rice producers in the manufacture of safe products. Although chemical disinfectants can be used to reduce the amount of B. cereus in rice, vitamin B1 can also be used as an effective additive that reduces the amount of disinfectant use via a synergistic antimicrobial effect. The increasing use of chemical disinfectants for safety in the food industry can be reversed using our method. 相似文献
PRACTICAL APPLICATIONS
The prevalence of Bacillus cereus in rice and rice products has been documented and control of the growth of B. cereus in rice is an important consideration. The results obtained from this study can be of use to rice producers in the manufacture of safe products. Although chemical disinfectants can be used to reduce the amount of B. cereus in rice, vitamin B
9.
ABSTRACT: Natrolite was used to explore a physical and safe method to decontaminate aflatoxin-containing pistachio lots. Pistachio nuts with low, medium, and high levels of aflatoxin were subjected to a washing process with a slurry of 5% natrolite. Using thin-layer chromatography and scanning, the aflatoxin contents of the samples were measured. Aflatoxins B1 and B2 were found in pistachio nuts. The majority of total aflatoxins was aflatoxin B1 Natrolite treatment resulted in a 38% to 100% reduction in aflatoxin B1 , depending on the initial aflatoxin level. Although natrolite was demonstrated to be an effective candidate to reduce aflatoxin B1 , its efficacy against aflatoxin B2 was limited. 相似文献
10.
M.M. Castelo L.S. Jackson M.A. Hanna B.H. Reynolds L.B. Bullerman 《Journal of food science》2001,66(3):416-421
The objective of this work was to determine the effect of added sugars on fumonisin B1 (FB1 ) levels in baked corn muffins and extruded corn grits. Muffins containing added glucose had significantly lower FB1 levels than muffins with sucrose, fructose, or no added sugar. Extrusion cooking of the grits resulted in significant (p< 0.05) reductions of FB1 in all treatments relative to unextruded controls, but use of glucose resulted in greater reductions of FB1 (45.3 to 71%) than did the use of fructose (29.5 to 53%) or sucrose (19.2 to 39%). When extrusion conditions were optimized, 92.1% loss of FB1 was found when grits were extruded with glucose. Adding glucose to thermally processed food can result in a substantial reduction in FB1 levels. 相似文献
11.
Experiments were designed to determine whether certain nontoxigenic fungi commonly isolated from maize kernels can affect aflatoxin B1 development when inoculated with A. flavus onto individual unsterilized, and autoclaved maize kernels . Trichoderma viride and Aspergillus niger were found to be strongly antagonist inhibiting the growth of A. flavus by 87 and 66% respectively, whereas Aspergillus versicolor, Fusarium moniliforme, Paecilomyces variotii and Emericella quadrillineata inhibited the growth of A. flavus by less than 51%. Less aflatoxin B1 was detected when A. flavus was paired with A. niger or T. viride than with the other test fungi. When A. niger or T. viride was introduced onto the kernels 72 h before inoculation with A. flavus, no aflatoxin B1 was detected in unsterilized kernels and the levels of aflatoxin B1 were greatly reduced from 700 ppb to 160 and 140 ppb in autoclaved kernels, respectively. When inoculation of A. flavus followed 72 h of incubation of either A. niger and T. viride, no aflatoxin B1 was detected. However, when both A. niger and T. viride were introduced 72 h after inoculation with A. flavus, the levels of aflatoxin B1 were reduced to 385 and 560 ppb, respectively in unsterilized and autoclaved maize kernels . Trichoderma viride and Aspergillus niger may be useful in biological control of aflatoxin contamination of maize kernels .; Accepted for Publication June 11, 1997 相似文献
12.
Loin sections of pork muscle were heated to 75 or 85°C internal temperatures in microwave or conventional electric ovens. Cooking losses and time, percentage moisture and total vitamin B6 were determined. Cooking time was longer, total cooking loss less and moisture content greater for pork cooked in an electric oven than for that cooked in a microwave oven. Differences in vitamin B6 due to type of oven or internal temperature were small and not significant when calculated on a cooked weight basis. When calculated on a dry weight basis samples cooked in the conventional oven contained more vitamin B6 than did those cooked by a microwave oven. 相似文献
13.
Two fungi, Boletus edulis and Agaricus bisporus, were tested as substrates for two known aflatoxigenic fungi, Aspergillus flavus ATCC 15548 and A. parasiticus NRRL 2999. Both autoclaved substrates supported mycelial growth, sporulation, and aflatoxin production; however, the B. edulis substrate allowed more rapid mold growth and greater toxin production than did the A. bisporus substrate under laboratory conditions. Both aflatoxins B1 and AFG1 were produced with AFG1 being the predominant toxin. Aflatoxins B2 and AFG2 were not detected. Although toxin was produced at low levels, the highest mean being 0.55 μg/g substrate for AFB1 and AFG1 , both mushrooms apparently contained minimal nutrients for toxigenic mold growth and failed to cause antimycotic or antiaflatoxigenic responses. Routinely used aflatoxin extraction and analytical procedures appear applicable for such testing of mushrooms. 相似文献
14.
The effects of administering low levels of aflatoxin B1 -14 C by crop intubation daily for 14 days to layer chickens were determined. Studies on the distribution of 14 C in the blood, selected organs, tissues, eggs and excreta were conducted. No toxic effects were observed in layer chickens during the course of the experiment. The layer chickens excreted 92.15% of the 14 C administered. Of the 14 C retained, 19.5, 16.1, 3.9, 7.2, 26.4 and 26.9% were detected in the blood, liver, heart, gizzard, breast and leg, respectively. No radioactivity was detected in egg samples collected. Chemical assay of those samples demonstrating radioactivity revealed that 81.2% of the radioactivity in these substrates was soluble in aqueous extracts while approximately 10% was ex tractable by classical extraction procedures. Treatment of the aqueous extracts for conjugated steroids by treatment with Beta-glucuronidase revealed that 31.5% of the 14 C detected in the aqueous extract was a liberated glucuronide conjugate of aflatoxin M1 −14 C 相似文献
15.
Mineral and water soluble vitamin content in the Kombucha drink 总被引:2,自引:0,他引:2
Biljana Bauer-Petrovska & Lidija Petrushevska-Tozi 《International Journal of Food Science & Technology》2000,35(2):201-205
Summary Biologically active substances (water soluble vitamins and minerals) were analyzed in 'Kombucha'—a curative liquor, produced by the so-called 'Kombucha cultivation' (Macedonian collection of microorganisms, No 734) in sweet black tea decoct. The water soluble vitamins in the Kombucha drink were separated and identified using thin layer chromatography (TLC) and quantified by the comparison of their chromatographic UV spectra with the reference compounds. Four soluble vitamins have been determinated to have the following concentrations: vitamin B1 0.74 mg ml−1 , vitamin B6 0.52 mg ml−1 , vitamin B12 0.84 mg ml−1 and vitamin C 1.51 mg ml−1 . Mineral elements of nutritional and toxicological importance were determined in dissolved ash using atomic absorption chromatography (AAS). Mineral composition content involved determination of the essential elements: zinc, copper, iron, manganese, nickel and cobalt. Investigations of some toxic elements showed that lead and chromium were present in very small amounts, whereas cadmium was not found. 相似文献
16.
ABSTRACT: Natural phytochemicals may be an alternative to synthetic chemicals for controlling fungal growth and mycotoxin production in stored maize. A key to progress in this field is to select the best natural maize phytochemicals to be applied in a storage maize ecosystem. This research was undertaken to evaluate the effects of the natural phytochemicals trans-cinnamic acid (CA) and ferulic acid (FA) alone at concentrations of 20 to 30 mM and in 5 combinations on Aspergillus flavus Link and A. parasiticus Speare populations and aflatoxin B1 production. Studies on Aspergillus population and aflatoxin B1 production were carried out in maize grain in relation to a water activity aw of 0.99, 0.97, 0.95, and 0.93. CA and FA at concentrations of 25 to 30 mM, respectively, and CA-FA mixture T9 (25 + 30 mM) were the treatments most effective at inhibiting A. flavus and A. parasiticus population at all aw assayed after 11 d of incubation. At all aw values, the mixture CA-FA T9 (25 + 30 mM) completely inhibited (100%) aflatoxin B1 production by both strains at aw = 0.99, 0.97, 0.95, and 0.93. Decreased aflatoxin B1 levels in comparison with the control were observed with mixtures CA-FA T6 (10 + 25 mM), T7 (20 + 20 mM), and T8 (20 + 30 mM) of both strains in the majority of aw assayed. The data show that CA and FA could be considered as effective fungitoxicants for A. flavus and A. parasiticus in maize in the aw range 0.99 to 0.93. The information obtained shows promise for controlling aflatoxigenic fungi in stored maize. 相似文献
17.
S. Marín N. Magan J. Serra A.J. Ramos R. Canela V. Sanchis 《Journal of food science》1999,64(5):921-924
Two isolates each of Fusarium moniliforme and Fusarium proliferatum isolated from maize were compared for growth and fumonisin B1 production on maize, wheat, and barley extract agars and on irradiated maize, wheat, and barley grain in relation to water availability and temperature. Growth rates of both Fusarium spp. were similar or higher on wheat and barley than on maize extract agar. Regardless of temperature, all isolates produced fumonisin B1 only on irradiated maize grain, but not on wheat or barley. This might be a reason for the low natural occurrence of fumonisins on those grains. 相似文献
18.
Phytic acid inhibition of Aspergillus flavus aflatoxin B1 production is well observed. Although this fungus grew well in Czapak-Dox medium, mycotoxin production was eliminated by adding a small amount of phytic acid. Possible reasons are discussed, and the importance of some metallic ions is observed. Results suggested that phytate may be an effective anti-AFB1 agent for preventing the contamination of the fungus. 相似文献
19.
A survey was undertaken to update and extend information on the water-soluble vitamin content of milk and milk products on retail sale. The results are discussed in relation to previously published data. Apart from vitamin C the levels of vitamins in retail pasteurized cows' milk were very similar to those found in milk from the processing dairy. Levels of total vitamin C and folic acid in UHT full cream milk were negligible; vitamin B6 and vitamin B12 were respectively 73 and 56% of the levels in pasteurized milk. Except for nicotinic acid, pantothenic acid and biotin, the levels of vitamins in sterilized milk were lower than in pasteurized milk, particularly vitamin C, folic acid and vitamin B12 . When compared on an equivalent dilution basis, vitamin B6 , thiamine, folic acid and, especially, vitamin B12 in evaporated milk were lower than in pasteurized cows' milk. In comparison, in full cream condensed milk only vitamin B6 was particularly low; vitamin C was particularly well preserved. With the exception of vitamin B12 , vitamin levels in reconstituted spray dried milk were similar to those in pasteurized cows 'milk. Levels in filled' spray dried milk were on average 70% of those in ordinary dried milks. Apart from vitamin B12 the levels of B vitamins in non health food yogurt were generally higher than in pasteurized milk, especially folic acid. The levels of vitamin B12 and folic acid in goats' milk were only 22 and 11 % respectively of those in cows' milk, but the nicotinic acid level was four times higher. The level of vitamin C in raw sheep's milk was about five times that in pasteurized cows' milk; other levels, apart from folic acid which was similar, were between 1.3 and 5.2 times those in cows' milk. 相似文献
20.
A fourteen hour exposure to sunlight destroys about 90 and 77% aflatoxin B1 added to groundnut flakes with and without fat whereas only about 50% of the toxin is destroyed when present as a natural contaminant. Treating the groundnut flakes with 20% urea and 2% soybean flour (a source of urease) at 50% moisture would bring about 70% destruction of aflatoxin B1 ; In large scale trials, destruction was about 85%. Treatment with urea does not bring down the PER value of the material, which is 1.5 after treatment as against 1.6 in the untreated groundnuts. 相似文献