Fungi and aflatoxins associated with spices in the Sultanate of Oman

One hundred and five samples of seven spices (cumin, cinnamon, clove, black pepper, cardamom, ginger, and coriander) were purchased from five popular companies in the Sultanate of Oman. The spices were surveyed for the mycoflora and aflatoxins. Twenty fungal species were isolated in which Aspergillus flavus , A. niger . Penicillium , Rhizopus , and Syncephalastrum racemosum were the most dominant. When colony forming units per gm (cfu/gm) of fungi were compared, significant differences were found among spices and companies. Of the seven spices studied, clove was found to be the least contaminated, while cumin was the most contaminated. None of the 15 selected samples of the spices contaminated by A. flavus were found to contain aflatoxins. Nevertheless, nine isolates (45%) of the twenty A. flavus strains screened for aflatoxins were aflatoxigenic. The moisture content of most of the spices was below the maximum standard limit. The results showed that the spices were contaminated by some fungi that might constitute health hazards for humans. This revised version was published online in June 2006 with corrections to the Cover Date.     

Contamination of common spices in Saudi Arabia markets with potential mycotoxin-producing fungi

Fifteen spices obtained from common markets were examined for their mould profile. A total of 520 fungal isolates, representing 57 species, were recovered and identified from dried and ground spice samples on three different media using standard dilution plate method. The most heavily contaminated spice samples examined were observed in ginger in order of magnitude of 5325–6800 cfu/g. The most predominant fungal genera encountered were Aspergillus, Penicillium, and Rhizopus. Relative occurrence values of taxa disclosed ranged between 80% for Aspergillusflavus, Aspergillusniger and Penicilliumarenicola, and 10% for some species. Samples obtained from sumac encountered very rare colony counts indicating its antifungal prosperities. The present magnitude of contamination and spectra of mycobiota approximate those reported for similar spice samples. Several potentially mycotoxigenic fungi were isolated from the majority of samples. The present study attracts the attention to potential risk for mycotoxins contamination may be caused as a result of using these spices, especially in great quantities. The study strongly recommends reduction in application of heavily contaminated spices like ginger in food processing and using some others like clove and sumac due to their antimicrobial properties.     

Natural occurrence of mycotoxins in different spices in Egypt

A total of 120 different samples belonging to 24 kinds of spices collected from different places atAssiut Governorate (Egypt) were examined for the natural occurrence of mycotoxins. TLC analysis of spice extracts revealed the presence of aflatoxins (8–35 μg/kg) in 16 samples of anise, black pepper, caraway, black cumin, fennel, peppermint, coriander and marjoram, sterigmatocystin (10–23 μg/kg) in ten samples of red pepper, caraway, cumin and marjoram and citrinin (8–12 ⧎g/kg) in two samples of black cumin, while ochratoxin A and zearalenone could not be detected.     

Mycoflora and mycotoxins of peanut (Arachis hypogaea L.) seeds in Egypt. 1-sugar fungi and natural occurrence of mycotoxins

Sixty-four species and 2 varieties which belong to nineteen genera of fungi were identified from 40 peanut seed samples collected from different places in Egypt by using a dilution-plate method on glucose-Czapek's medium. The most frequent genera were Aspergillus (21 species & 2 varieties), Penicillium (16 species) and Fusarium (6 species). A. flavus, A. fumigatus, A. niger, P. chrysogenum and F. oxysporum were the most common fungal species. Forty seven percent of the samples proved to be toxic to brine shrimp (Artemia salina) larvae. Thin-layer Chromatographic analysis revealed that peanuts were contaminated by aflatoxins (11 samples), thrichothecene-toxins (10 samples), zearalenone (one sample) and citrinin (one sample). We believe that this is the first report of the natural occurrence of zearalenone and trichothecene-toxins in peanuts.     

Fungal contamination of some imported spices

Seventeen imported raw spice samples obtained from retail outlets were examined for spoilage mould profile. A total of 665 fungal isolates, representing 14 species, were recovered and identified from dried and ground spice samples on several media using standard dilution plate method. Moisture content varied greatly among various samples and were generally high. The most heavily contaminated spice samples examined were observed in red chili and black pepper in order of magnitude of 1580 and 1120 cfu/g, respectively. The most predominant fungal genera encountered were Aspergillus, Penicillium, Rhizopus, Cladosporium and Trichoderma. Yeasts were also frequently recovered, but not identified. Relative occurrence values of taxa disclosed ranged between 36.4% for A. flavus and 0.6% for A. parasiticus and Absidia corymbifera. Samples obtained from gunny bags encounter higher colony counts and contamination frequency than other packing methods. The present magnitude of contamination and spectra of mycobiota approximate those reported for similar spice samples. Although several potentially mycotoxigenic fungi were isolated during the present study, neither the foodstuff nor the fungi were assayed for the presence of these toxins.     

Decrease of growth and aflatoxin production in Aspergillus parasiticus caused by spices

Non-commercial spices and herbs Tetrapleura tetrapetra, Triumfetta cordifolia, Garcina kola, Monodora myristica and Xylopia aethiopica at 0.08 to 0.32% (w/v) decreased the mycelial weight of Aspergillus parasiticus NRRL 2999 in yeast extract/sucrose broth by up to 68%. Aflatoxin production, monitored with ELISA, was most effectively decreased, from 97 to 23 g/ml, when the extract of G. kola was added at 0.32% (w/v).     

Occurrence of the non-phosphorylative pathway for gluconate degradation in different fungi

The presence of the non-phosphorylative pathway for gluconate degradation in several different fungi has been determined. The pathway was found to be present to varying extents in Penicillium and Mucor species, but was not detected in Fusaria and some Aspergillus. Most of the organisms tested were able to grow on gluconate as the sole source of carbon.     

Mycoflora and mycotoxins of peanut (Arachis hypogaea L.) seeds in Egypt. III. Cellulose-decomposing and mycotoxin-producing fungi

From 40 peanut seed samples collected in Egypt, forty-three species and one variety of fungi, belonging to 16 genera, were collected. The most dominant genera were Aspergillus (11 species + one variety), Penicillium (11 species) and Fusarium (4 species). From the preceding genera A. fumigatus, A. flavus, A. niger, P. chrysogenum and F. oxysporum were the most frequent species.Forty-nine isolates belonging to 12 species and one variety were tested for production of mycotoxins, after growth on liquid medium containing two carbon sources (sucrose or cellulose). Thin layer chromatographic analysis revealed that the quality and quantity of mycotoxins was higher on sucrose than cellulose. Mycotoxins identified were aflatoxins B₁, B₂, G₁ & G₂, citrinin; fumagillin; diacetoxyscirpenol T-2 toxin; satratoxin H; and zearalenone.     

Mycotoxigenic fungi in peanuts from different geographic regions of Egypt

To understand the importance of mycotoxigenic fungi in Egyptian peanuts, samples from five regions (Alexandria, El-Beheira, El-Sharqiya, El-Daqahelaya in northern Egypt and Asyut, southern Egypt) in two seasons (2007, 2008) were collected. Aspergillus was consistently the most frequent genus in seeds and in-shell peanuts and was the dominant mycotoxigenic component of the mycobiota. There was no direct correlation between the moisture content of the samples and the fungal populations on peanut seeds tested from different regions. The most common species were from Aspergillus section Flavi (4.7-78.3%), Aspergillus section Nigri (9.4–52.6%) and Aspergillus section Circumdati (5.1–30.9%). In the in-shell peanut samples, the lowest populations were recorded in El-Beheira and Asyut (3.7–4.0 log₁₀ CFU g^-1) and the highest in Alexandria and Elsharqiya (4.1–6.0 log₁₀ CFU g^-1). Aspergillus section Flavi and section Nigri were the most dominant, and Aspergillus section Circumdati were only found in samples in 2008. Both qualitative (coconut cream agar) and quantitative analyses (HPLC) were used to analyse the potential mycotoxin production by strains isolated from peanuts. Of a total of 88 Aspergillus section Flavi strains examined, 95% were A. flavus based on production of aflatoxin B₁ on yeast extract sucrose (YES) medium and confirmation using molecular analyses. Of 64 Aspergillus section Circumdati strains only 28% produced ochratoxin A (OTA), and were identified as A. westerdijkiae. No Aspergillus section Nigri strains produced OTA, and they were identified as A. niger (uniseriate). The presence of these toxigenic fungi indicates that there is a potential risk of mycotoxin contamination in Egyptian peanuts and suggests that problems can arise from contamination with both aflatoxins and perhaps also OTA.     

Inhibitory effect of garlic on bacterial pathogens from spices

An unconventional technique for primary screening of bacterial susceptibility to garlic (Allium sativum Linn.), using a slice from its clove, was described. Aqueous extracts of garlic were found to possess a potent bacteriostatic principle against Gram-positive as well as Gram-negative foodborne bacterial pathogens. In agar medium, the minimum inhibitory concentrations (MICs) of garlic were 6–10 mg ml^–1 for Bacillus cereus, 30–40 mg ml^–1 for Staphylococcus aureus (excepting the isolate from garlic, where the MIC was 100 mg ml^–1), 20–30 mg ml^–1 for Clostridium perfringens, 10 mg ml^–1 for Escherichia coli (30 mg ml^–1 for the garlic isolate), 40–100 mg ml^–1 for Salmonella, and 10–40 mg ml^–1 for Shigella. It inhibited the growth of all these strains, which were resistant to some commonly used antibiotics. Most of the tested strains were resistant to penicillins, although sensitive to garlic. While the growth of B. cereus and Cl. perfringens was completely inhibited at 10 and 70 mg garlic, respectively, ml^–1 test broth, their respective enterotoxin production ceased at 10 and 50 mg garlic ml^–1.     

Element analysis and biological studies on ten oriental spices using XRF and Ames test

Ten oriental spices were analyzed for their element composition using X-ray fluorescence (XRF): nutmeg (Myristica fragrans), coriander (Coriandrum sativum), safflower (Carthamus tinctorius), caraway (Carum carvi), Sicilian sumac (Rhus coriaria), aniseed (Anisum vulgare), black pepper (Piper nigrum), cardamom (Elettaria cardamomum), cumin (Cuminum cyminum) and nigella (Nigella sativum). The spices were found to contain the following elements: Mg, Al, Si, P, S, Cl, K, Ca, Ti, Mn, Fe, Cu and Zn, with varying concentrations. Mutagenic studies using Salmonella typhimurium strains TA97a, TA98, TA100, and TA102 showed that the above spices have no base pair substitution mutagenic activity. However, a weak frameshift mutagenicity has been shown by nutmeg and a very weak oxidative mutagenic action has been revealed by cumin.     

Isolation of keratinophilic fungi from floor dust in Arab elementary and preparatory schools in the West Bank of Jordan

Floor dust collected from classrooms of thirty three elementary schools (16 for girls, and 17 for boys) (children aged 6–11), and twenty four preparatory schools (13 for girls, and 11 for boys) (children aged 12–14) was studied for the occurrence of keratinophilic fungi with respect to human presence and age of children. Tichophyton mentagrophytes was present in 15.4% of the preparatory schools for girls, in 12.5% of elementary schools for girls, and in 11.8% of elementary schools for boys. It was not found in preparatory schools for boys. Microsporum gypseum was found in preparatory schools for girls only (7.7%). Trichophyton terrestre was also only isolated from elementary schools for boys (5.9%). Chrysosporium species were present in 30.3% of all elementary schools (10 schools/33), and in 20.8% of all preparatory schools (5 schools/24). Geotrichum candidum was the most frequent and predominant keratinophilic species in all schools. Pathogenic and potentially pathogenic keratinophilic fungi comprised a large proportion of all fungal isolates recovered from all schools ; they comprised 87.2 %–89.5 % of all fungal isolates in the elementary schools, and 90.4%–93.5% of all fungal isolates in preparatory schools.     

Survey of the mycoflora and mycotoxins of cotton seeds and cotton seed products in Egypt

Thirty-nine species and 16 fungal genera were isolated from Egyptian cotton seeds, cotton seed meal and cotton seed cake on 1% glucose-Czapek's agar medium incubated at 28 °C. Aspergillus was the most frequent genus and it emerged in 87–100% of the samples contributing 70–98% of total fungi in the three substrates tested. The most common species were A. niger, A. flavus, A. fumigatus, A. terreus and Rhizopus stolonifer; A. niger, A. fumigatus and Penicillium corylophilum; and A. niger, A. flavus, A. terreus, A. nidulans and Rhizopus stolonifer, respectively. Cotton seeds and cotton seed products were naturally contaminated by aflatoxin B₁ and B₂. About 16% of the different substrates tested were positive for aflatoxin contamination. No citrinin, ochratoxin A, patulin, sterigmatocystin, diacetoxyscirpenol, T-2 toxin or zearalenone were detected in the samples assayed.     

根癌农杆菌介导真菌遗传转化的研究进展

根癌农杆菌介导的真菌遗传转化是近年来发展的一种新方法 ,与其它方法相比 ,该方法具有操作简便、转化效率高和易得到稳定转化子等特点。目前 ,在根癌农杆菌介导下已实现了多个属种真菌的遗传转化 ,显示出良好的应用前景。综述了根癌农杆菌介导真菌遗传转化的转化机理和T DNA在真菌细胞中的存在方式等方面的研究结果 ,并展望这一方法的应用前景。     

Intracellular protein breakdown in thermophilic and mesophilic fungi

1. The rate of protein breakdown was determined on growing and non-growing cultures of thermophilic and mesophilic fungi. 2. In growing cells protein breakdown was negligible. 3. In non-growing cells the breakdown rate of total protein varied between 5.2%/h and 6.7%/h. These values were found to be dependent on both the temperature of the protein breakdown assay and the temperature of growth of the organism. 4. The rate of breakdown of soluble protein in thermophilic fungi was 9-15%/h whereas the rate in mesophilic fungi for the soluble protein fraction was only 4%/h.     

Comparison of biosorption properties of different kinds of fungi for the removal of Gryfalan Black RL metal-complex dye

Three kinds of filamentous fungi (Rhizopus arrhizus, Trametes versicolor, Aspergillus niger) were tested for their ability to adsorb Gryfalan Black RL metal-complex dye as a function of pH, temperature and dye concentration. R. arrhizus and T. versicolor exhibited the maximum dye uptake at pH 2.0 and at 25 degrees C while A. niger performed the highest dye biosorption at pH 1.0 and at 35 degrees C. Sorption capacity of each biosorbent increased with increasing initial dye concentration. Among the three fungi, R. arrhizus was the most effective biosorbent showing a maximum dye uptake of 666.7 mg g(-1). The Langmuir model described the equilibrium data of each dye-fungus system accurately in the concentration and temperature ranges studied. Kinetic analysis indicated that both adsorption kinetics and internal diffusion played an important role on controlling the overall adsorption rate for each fungus. Thermodynamic analysis verified that A. niger biosorption was endothermic while the others were exothermic.     

Diversity and functioning of fungi associated with leaf litter decomposition in Asian forests of different climatic regions

The pattern of diversity and functioning of fungi associated with leaf litter decomposition in Asian forests of different climatic regions was investigated by performing meta-analysis of published data for seven tree species in subalpine, temperate, subtropical and tropical forests. Fungal assemblages were examined by using common standard isolation-culture methods, and the abilities of individual fungal species to decompose leaf litter were examined with pure culture decomposition tests. The climatic patterns of diversity, assemblage structure and genus composition depended on the method of isolation: the washing method revealed no consistent pattern, whereas the surface sterilization method showed lower diversity and greater relative abundance of dominant fungal species within the assemblages in cooler climates. The decomposing ability of species within fungal assemblages was greater in warmer than in cooler climates and in broad-leaved than in coniferous tree species. In particular, the greatest abilities to cause mass loss were found among fungi with ligninolytic activity in broad-leaved tree species in warmer climates.     

Fungal populations and mycotoxins in silage in Assiut and Sohag governorates in Egypt,with a special reference to characteristic Aspergilli toxins

Forty silage samples were collected from Assiut and Sohag governorates in Egypt to measure the presence of fungal population in silage. Forty-three species and 2 species varieties belonging to 17 genera were isolated using glucose Czapeks and Sabourauds dextrose agar media at 28 ^°C. The most prevalent genera were Aspergillus (57.5 and 100 of the samples), Penicillium (100 and 55%) on the two mentioned media, respectively. Also, Fusarium oxysporum and Gibberella fujikurori were recovered in moderate incidences. Mycotoxin profiles were also determined in these samples: Aflatoxins showed the highest incidence rates of occurrence, it occurred in 22.5% of all samples analyzed. Other mycotoxins were detected from all samples (T₂ toxins and sterigmatocystin at incidence of 7.5 and 5%, respectively). The screening of the characteristics mycotoxins of different isolates of Aspergillus isolated from silage samples was tested. The results clarified that some mycotoxins (aflatoxins – aspergillic acid – beta nitro propionic acid – cyclopiazonic acid– kojic acid and sterigmatocystin) were produced by some isolates of A. flavus. Some isolates of A.fumigatus could produce gliotoxin and verrucologen. All of A. niger isolates tested were able to produce kojic acid. One isolate of A. ochraceous formed ochratoxin A and other isolate produced penicillic acid. Concerning A. terreus isolates, the results showed that 5 isolates were able to produce citrinin and 4 isolates had ability to produce patulin. A. versicolor isolates showed the ability to produce ochratoxin A.