Mycotoxic flora and mycotoxins in smoke-dried fish from Sierra Leone

Examination of 20 samples of smoke-dried fish of the Ethmolosa sp. commonly called “Bonga”, from homes and markets in Njala (Sierra Leone) revealed the presence of 4 Aspergilli species: A. flavus Links ex Fries, A. ochraceus Wilhelm, A. tamarii Kita and A. niger van Tieghem. Fresh or properly preserved smoke-dried fish showed no signs of fungal contamination. Mouldy fish extracts contained varying amounts of aflatoxins B₁, G₁, G₂ and ochratoxin A. Isolates of A. flavus grown on yeast extract sucrose (YES) medium, produced considerable amounts of aflatoxin B₁ and G₁ and trace amounts of G₂. On YES medium A. ochraceus produced large amounts of ochratoxin A but no penicillic acid.     

Quality of cassava foods in Sierra Leone

Gari and foofoo (fermented cassava foods) were purchased in the Freetown markets of Sierra Leone and analysed for factors associated with quality. Sellers were generally knowledgable about the source of the products which all originated from the country areas outside Freetown. The mean cyanide contents were higher (8.6 mg kg^?1 DM for gari and 28.2 mg kg^?1 DM for foofoo) than the amounts suggested by the Codex specification and, because of the distribution of the values around the mean, some samples necessarily contained unacceptable amounts of cyanide. Cyanogens were present as the cyanohydrin or as free cyanide; no glucoside was detected. Microbiological analysis of the samples showed high counts for total organisms, fungi and Enterobacteriaceae (10⁶–10⁷ g^?1). The mean water content of gari was 119 g kg^?1 which falls within the recommended limit of 120 g kg^?1 but again, due to the distribution of values around the mean, some samples had considerably higher water contents than that limit. Titratable acidity and pH were measured and the mean pH values were 4.18 for foofoo and 4.55 for gari. The particle size and swelling power of gari samples were also measured as these relate to consumer acceptance. The data show the quality of current cassava foods marketed in a major urban centre in Sierra Leone. As centralised processing develops, improvements can be made to those quality parameters which have been identified as important.     

Microbial flora of fresh and smoked fish from Nigerian fresh-water

Bacteria isolated from fresh Clarias lazera fish caught from the Ogurugu River in Nigeria were Micrococcus, Lactobacillus, Acinetobacter, Klebsiella, Aeromonas, Pseudomonas, Enterobacter, Flavobacterium, Moraxella and coryneforms. Micrococcus, Lactobacillus and Acinetobacter were isolated from fish smoked at 38–43°C but only Micrococcus came from fish smoked at 65–78°C. Smoked fish bought on the open market, in addition to Micrococcus, Lactobacillus and Acinetobacter, yielded Bacillus, Staphylococcus, Proteus and Escherichia. Bacillus cereus was also recorded on such fish but Vibro cholera, Salmonella, Shigella and Clostridium spp. were absent on both fresh and smoked fish.     

Survey of roasted street-vended nuts in Sierra Leone for toxic metabolites of fungal origin

Consumption of mycotoxin contaminated foodstuffs is common in regions where foods are not adequately controlled and routinely monitored, and this could have adverse effects on the health of consumers. In this study, 100 samples of roasted nuts (50 cashew nuts and 50 peanuts) vended within two cities of Sierra Leone were analysed for mycotoxins and other microbial metabolites by a LC-MS/MS method. The peanut samples contained detectable levels of 17 microbial metabolites, including aflatoxins B₁, B₂, G₁ and G₂ and alternariol, while none of these metabolites were found in the cashew samples. Aflatoxins (max: 5,729 μg/kg; mean: 487.8 μg/kg) and alternariol (3 μg/kg) were found in 24% and 2% of the peanut samples, respectively. One-third of the aflatoxin-contaminated peanut samples contained aflatoxins at levels exceeding the total aflatoxin limit of 4 μg/kg set by the European Union. Aflatoxin contamination of Sierra Leonean peanuts is high and requires urgent intervention to reduce consequent exposure.     

Fusarium mycotoxins in cereals harvested from Hungarian fields

The Fusarium mycotoxins deoxynivalenol (DON), zearalenone (ZEN) and T-2 frequently contaminate grain crops in Middle and Eastern Europe. In this survey, 116 cereal samples (maize, wheat, barley and oat) were examined for DON, ZEN and T-2 mycotoxins. Samples were collected from different areas in two Hungarian regions (North and South Transdanubia). The method of analysis was indirect competitive ELISA. Maize was the most contaminated grain regarding DON (86%), ZEN (41%) and T-2 (55%) toxins. The average results of the deoxynivalenol and zearalenone tests of maize proved to be significantly higher than those of barley or oat. DON was the most represented Fusarium mycotoxin followed by T-2 and ZEN. The examination of these mycotoxins would be necessary at a larger scale as to re-evaluate permissible levels, so increase of the monitoring programme would be advisable for the future.     

Moulds and mycotoxins in rice from the Swedish retail market

A survey of moulds and mycotoxins was performed on 99 rice samples taken from the Swedish retail market. The main objective was to study the mould and mycotoxin content in basmati rice and rice with a high content of fibre. Samples of jasmine rice as well as long-grain rice were also included. The samples were analysed for their content of ochratoxin A (high-performance liquid chromatography (HPLC)), aflatoxin B₁, B₂, G₁, and G₂ (HPLC, RIDA®QUICK), and mould (traditional cultivation methods in combination with morphological analysis). The majority of samples were sampled according to European Commission Regulation 401/2006. Subsamples were pooled and mixed before milling and both mould and mycotoxin analyses were performed on milled rice. The results showed that the majority of basmati rice (71%) and many jasmine rice samples (20%) contained detectable levels of aflatoxin B₁ (level of quantification = 0.1 µg aflatoxin kg^?1 rice). Two samples of jasmine rice and ten basmati rice samples contained levels over the regulated European maximum limits of 2 µg kg^?1 for aflatoxin B₁ or 4 µg kg^?1 for total aflatoxins. Aspergillus was the most common mould genus isolated, but also Penicillium, Eurotium, Wallemia, Cladosporium, Epicoccum, Alternaria, and Trichotecium were found. The presence of Aspergillus flavus in 21% of the samples indicates that incorrect management of rice during production and storage implies a risk of mould growth and subsequent production of aflatoxin. Rough estimates showed that high rice consumers may have an intake of 2–3 ng aflatoxin kg^?1 bodyweight and day^?1 from rice alone. This survey shows that aflatoxin is a common contaminant in rice imported to Europe.     

Identities of the Pseudomonas spp. in flora from chilled chicken.

Nine broilers from each of two different broiler farms were collected at the slaughterhouse. Microbiological samples were collected from broiler chicken carcasses which were stored aerobically at 3+/-0.5 degrees C for 0, 3 or 8 days. By characterizing 40 colonies per broiler it was possible to evaluate the shift in psychrotrophic bacteria on the skin during cold storage. Most of these bacteria belong to the pseudomonads. The Shewan scheme was used in order to distinguish between four groups of pseudomonads. On fresh poultry group II pseudomonads were most abundantly represented, followed by group IV; group I and III strains were present in lower amounts. Non-fluorescing group II pseudomonads always predominated as spoilage became obvious (day 8). By including 36 reference strains, numerical analysis based on the simple matching coefficient was performed on 180 representatively selected strains. This revealed that Pseudomonas species indeed predominated when spoilage was obvious. Non-fluorescing species were identified mainly as P. fragi, but also as other strains belonging to P. fluorescens biovars A, B, C and F, P. lundensis and cluster 7 strains (unidentified). Microorganisms already substantially present on the fresh poultry were found in the highest numbers at the time of spoilage.     

Co-occurrence of Fusarium mycotoxins in mouldy and healthy corn from Korea

A total of 71 samples consisting of 36 mouldy and 35 visibly healthy corn were collected from Kangwon province of Korea and analysed for 8-ketotrichothecenes, zearalenone (ZEA), and fumonisins, including fumonisin B1 (FB1), fumonisin B2 (FB2), and fumonisin B3 (FB3). Five 8-ketotrichothecenes, namely deoxynivalenol (DON), 15-acetyldeoxynivalenol (15-ADON), 3-acetyldeoxynivalenol (3-ADON), nivalenol (NIV), and 4-acetylnivalenol (4-ANIV), ZEA, FB1, FB2, and FB3 were detected in corn samples. DON, 15-ADON, 3-ADON, NIV, 4-ANIV, ZEA, FB1, FB2, and FB3 were detected in mouldy corn with mean values of 4.0, 0.9, 0.2, 1.7, 0.4, 0.6, 23.2, 7.5, and 6.3mug/g, respectively. Visibly healthy corn samples were contaminated with lower levels of 8-ketotrichothecenes, ZEA, and fumonisins than mouldy corn samples. However, 5 of 35 healthy corn samples analysed were contaminated with fumonisins at high levels up to 12.5mug/g for FB1, 5.4mug/g for FB2, and 0.5mug/g for FB3. This is the first report on the simultaneous occurrence of trichothecenes, ZEA, and fumonisins in corn from Korea.     

Mycobiota and mycotoxins in Brazilian peanut kernels from sowing to harvest

The total mycobiota and the mycotoxin contamination of peanuts were analyzed in plants collected at different stages of the pod maturity sampled in Junqueirópolis, at S?o Paulo State (Brazil). The prevalent peanut mycobiota were Fusarium spp. and Aspergillus flavus, present in 26% and 17% respectively of the samples analyzed. In soil, the genus Penicillium and Fusarium were most frequently detected, and A. flavus was detected in 8% of the samples. The screening of mycotoxins indicated that aflatoxins and cyclopiazonic acid were present the highest incidence, being detected in 32% of the samples, in concentrations, respectively, from 4.20 microg/kg to 198.84 microg/kg and from 260 microg/kg to 600 microg/kg. Fumonisins were not detected by HPLC. All data were correlated with the occurrence of wind-dispersed fungi and the environmental and soil conditions. Results indicate that good management of the agricultural environment may offer a way to reduce mycotoxins and the toxigenic fungal contamination in peanuts preharvest because the pods are exposed to different environmental conditions during their formation until harvest, and the optimal conditions for mycotoxin production and fungal growth are frequently found in the crop fields.     

Identification and quantification of fungi and mycotoxins from Pu-erh tea

Pu-erh tea originates from the province of Yunnan in south-western China. As this tea is produced by so called Aspergillus post-fermentation the question arises which molds and mycotoxins may be found in this tea. In total 36 samples of Pu-erh tea were investigated for their content of filamentous fungi and the mycotoxins aflatoxins B₁, B₂, G₁, and G₂, fumonisins B₁, B₂, and B₃, and ochratoxin A. Fungi were isolated from all samples in a concentration of 1.0 × 10¹ to 2.6 × 10⁶ colony forming units (cfu)/g tea, all together 19 fungal genera and 31 species were identified. The most prevalent species were Aspergillus acidus and Aspergillus fumigatus, followed by Zygomycetes and Penicillium species. Aflatoxins and fumonisins were not found in the samples investigated, ochratoxin A was detected in 4 of 36 teas (11.1%).     

梨火疫病菌活菌快速定量检测方法的建立

目的：为建立一种叠氮溴化丙锭（Propidium Monoazide,PMA）与实时定量聚合酶链式反应（Quantitative real-time Polymerase Chain Reaction,qPCR）联用的快速检测扩展青霉活菌方法。方法：通过优化PMA处理浓度、黑暗孵育及曝光时间,筛选扩展青霉特异性引物,结合qPCR技术,建立一种基于PMA-qPCR联用快速检测扩展青霉活菌的方法,构建定量标准曲线,应用于人工污染的苹果样品中活菌的检测,与平板菌落计数比较评估该方法的可靠性。结果：PMA处理浓度10 µg/mL、黑暗孵育5 min、曝光10 min为最佳PMA处理条件。4种引物中Pexp-patF对扩展青霉具有极强的特异性,可作为引物用于PMA-qPCR检测。构建的定量标准曲线的R²=0.9948,最低检测限为10^2.6 CFU/mL,方法检测结果与平板菌落计数无明显差异,并发现在苹果的未腐烂部分中可检测出扩展青霉活菌。结论：研究建立的PMA-qPCR技术可应用于苹果中扩展青霉活菌的检测,为扩展青霉精准防控提供一定技术支撑。     

Purification and Partial Characterization of Trypsin from the Viscera of Tropical Sierra (Scomberomorus Sierra) from the Gulf of California

Trypsin from the viscera of sierra (Scomberomorus sierra) was purified by affinity chromatography on Sepharose‐4B coupled to soybean trypsin inhibitor and characterized with respect to its purity, sensitivity to temperature, pH and inhibition. Trypsin was purified from sierra viscera with 11.9‐fold and 29.7% yield. The enzyme had a molecular weight of 25.4 kDa estimated by SDS‐PAGE and two possible trypsin isoforms were observed in activity gels. Trypsin activity was strongly inhibited by soybean trypsin inhibitor and porcine trypsin inhibitor, showing a partial inhibition by a serine protease inhibitor. The optimal activity of the enzyme was observed at pH 9 and 60C with n‐α‐benzoyl‐dl‐arginine‐p‐nitroanilide as a substrate. The enzyme maintained more than 50% of its activity in temperatures up to 50C and within the pH range of 8–10 for a period of up to 2 h.     

Silage from tropical fish 1. Proteolysis

Acid silages were prepared from silverbelly ( Leiognathus sp.) at 30°C with 3% (w/w) of 98% formic acid. After 14 days, total protein solubilization was 45-50%, of which 80% was TCA soluble and collagen solubilization was 42%. Centrifugation of 14 day old silage gave a cystine-rich undigested sediment and a liquor with a low tryptophan content. Gel chromatography of the liquor of a 14 day old silage showed it to be composed of at least two fractions: one consisting of protein fragments of molecular weight greater than 5000 daltons and the other of free amino acids and small peptides. Soluble collagen breakdown products were found predominantly (75%) in the high molecular weight fraction. A mechanism for the solubilization of collagen by the action of acid pH, elevated temperature and non-specific proteases is proposed. The limited autolysis in silverbelly silage is compared with that found in cold water fish silages and attributed principally to the resistance of warm water fish collagen to the effects of acid pH and temperature during ensilation.     

Co-occurrence and risk assessment of mycotoxins in food and diet from Mediterranean area

The contents of 14 mycotoxins were studied in samples of different cereals and cereal products from four countries of the Mediterranean region. Two hundred and sixty-five samples from Spain, Italy, Morocco and Tunisia were analysed. Samples were extracted with matrix solid-phase dispersion (MSPD) and determined by liquid chromatography-tandem mass spectrometry with a triple quadrupole mass analyser. The percentage of total samples contaminated was 53%. The frequency of contaminated samples from Spain, Italy, Tunisia and Morocco was 33%, 52%, 96% and 50%, respectively. Nivalenol and beauvericin were the most predominant mycotoxins. This is the first international report to study the presence of several mycotoxins in different types of cereal (rice, wheat, maize, rye, barley, oat, spelt and sorghum) and cereal products (snacks, pasta, soup, biscuits and flour) from the Mediterranean area, estimate the intake of mycotoxins and evaluate the risk assessment.     

Occurrence of mycotoxigenic fungi and mycotoxins in animal feed from bihar,india

A total of 387 samples comprising animal feed, poultry feed and cattle cakes from India were examined in order to isolate mycotoxin-producing fungi as well as mycotoxins. Of 385 Aspergillus flavus group isolates 53% were capable of producing aflatoxins in liquid SMKY medium. Toxigenic strains of other mycotoxigenic fungi, viz A ochraceus, A versicolor, Penicillium citrinum and Fusarium moniliforme, were also recorded. In feed samples, beside the aflatoxins present in 139 samples zearalenone, ochratoxin A and citrinin were also recorded alone or as cocontaminants. A monsoon climate together with the socioeconomic conditions of this region are important determinants for the high incidence of mycotoxins in animal food.     

Polychlorinated biphenyls in fresh and canned fish from the Central Adriatic.

By using the GLC method, levels of polychlorinated biphenyls (PCBs) were determined in fresh and canned fish during the 1984-88 period. Forty-six samples of fish caught in the Central Adriatic's littoral, 11 of which in a control, non-industrialized area, and 35 in an urbanized area strongly affected by industry, were collected. Also, 101 samples of canned fish were tested for PCBs. The average PCB values were 0.059 mg kg-1 and 0.287 mg kg-1 in control and polluted areas, respectively; the mean value in canned fish was 0.194 mg kg-1. Although the levels of PCBs in control and industrialized areas were found to differ, the difference was not significant statistically.     

Silage from tropical fish 2. Undigested fraction

The solubility of the undigested fraction (sediment) of a silage made from silverbelly ( Leiognathus sp.) in sodium dodecyl sulphate, guanidine hydrochloride and 2-mercaptoethanol, alone and in combination was evaluated. The sediment was probably composed of muscle proteins cross linked by disulphide bonds and stabilized by hydrophobic associations and hydrogen bonds. Ensilation followed by in vitro digestion of the sediment with pepsin/pancreatin/trypsin or in vivo digestion of the sediment using chicks, solubilized about 81% and 90% respectively of total nitrogen in silages up to 14 days old. The most resistant fraction was rich in collagenous derived material and bones. It is suggested that controlled ensilation can produce a highly digestible protein source without the formation of large amounts of reactive and labile free amino acids.