Chrysosporium species, potential spoilage organisms of chocolate

Standard methods of analysing foods for the presence of moulds are inadequate for thedetection of genera such as Chrysosporium which do not grow at the high wateractivities of most mycological media. The use of malt, yeast, 50% glucose agar (MY50G) insealed containers as an enrichment medium allowed time for germination and growth ofheat-stressed spores. Three Chrysosporium spp., C. xerophilum Pitt, C. inops (Carmichael) and C. farinicola (Burnside) Skou, were isolated fromcommercial chocolate bars with a water activity (a _w ) of approximately0·28. Chrysosporium inops was isolated from commercial milk crumb and anew Chrysosporium sp. was isolated from Ghanaian cocoa beans. In chocolates madeby coating MY50G agar (a_w = 0·89) with chocolate (a_w = 0·27) containing C. inops arthroconidia, two types of deterioration were seenafter storage. The first was fat bloom due to recrystallization of the cocoa butter on the outer andinner chocolate surface. The second was growth of C. inops which occurred on theinside chocolate surface adjacent to the MY50G agar filling and on the outside surface afterholding at 92% equilibrium relative humidity (erh) for 12 d. There was some evidence that C. inops could grow on the outside of chocolates held at 5·7% erh after 4months' storage at 25 °C. The appearance of the white fungal growth was not unlikefat bloom to the naked eye but was clearly different with the electron microscope.     

Vibrios of some deep-water invertebrates

Abstract The gut microbiota of 7 species of deep-water (300–400 m) invertebrates from the Gulf of Mexico was examined. High populations of Vibrio spp. were observed in crustaceans (ranging from 10⁵ to 7 × 10⁶ cells/g gut content) while relatively low populations of Vibrio spp. were found in annelids, the water column, and sediment. Although saprophytic Vibrio species were isolated, Vibrio fluvialis and Vibrio hollisae , potential human pathogens, were isolated from the crustaceans, Pleoticus robustus, Nematocarcinas sp., Plesionika sp., and Munida sp., and Vibrio vulnificus was isolated from Nereis sp. These observations confirm the finding of Ohwada et al. [18] that the gut of deep-water invertebrates has a bacterial flora abundant in Vibrio spp. These results also suggest that some marine invertebrates may serve as reservoirs for certain potential pathogenic Vibrio species.     

The occurrence of Aeromonas species in drinking water supplies of an area of the Dolomite Mountains, Italy

A study was made of the occurrence of Aeromonas spp. in drinking water supplies in a mountain area in northeast Italy (the Dolomites). On account of its location, the water in question is exposed to a low level of pollution and systematic chemical disinfection is not necessary. Out of 7395 water samples analysed over a 3 year period, 1623 (21·95%) were found to be positive for Aeromonas , with levels ranging from 1 to 240 cfu 100 ml⁻¹ ; 72·4% of the strains were identified as Aer. hydrophila , 14·7% as Aer. caviae and 12·9% as Aer. sobria. The percentage of recovery from surface water (approximately 40%) was found to be higher than that of ground water (springs : 24·9% ; wells : 28·6%). Aeromonas spp. were isolated from 21·7% of samples from the distribution network and showed no significant variations compared with water from reservoirs. There was no evidence, therefore, of after-growth in the distribution system. No correlation was found between the concentrations of Aeromonas spp. and faecal indicator organisms. As the distribution of Aeromonas spp. was unrelated to anthropic pollution, it is believed that the search for these micro-organisms should be adopted as a further indicator of drinking water quality, especially in waters such as those in the present investigation not undergoing systematic purification treatment.     

Isolation of human colonic fibrolytic bacteria

Bacteria able to degrade pebble-milled filter paper cellulose (PMC) were detected in only two of five human faecal samples and at very low concentrations ( ca 100/g faeces). For another sample, the most probable number of cellulolytic organisms was 8·7 times 10⁸/g with pebble-milled cell walls of New Zealand spinach as substrate, whereas PMC was not degraded. The cellulolytic bacteria isolated from those samples have been tentatively identified as atypical Ruminococcus spp. (two strains) and Eubacterium sp. A hemicellulolytic Butyrivibrio fibrisolvens was also isolated.     

Characterization of psychrotolerant heterotrophic bacteria from Finnish Lapland

A total of 331 aerobic heterotrophic bacterial strains were isolated from various ecosystems of Finnish Lapland (68-69 degrees N) including forest soil, arctic alpine-tundra soil, stream water, lake and mire sediments, lichen and snow algae. Whole cell fatty acid and 16S rRNA gene sequence analysis and microscopy indicated that the isolates were dominated by Gram-negative bacteria, while only 20 Gram-positive strains were isolated. Based on 16S rRNA gene sequences the isolates were members of alpha-, beta-, gamma-Proteobacteria, Gram-positives with low G+C content, Actinobacteria and the Cytophaga/Flexibacter/Bacteroides group. More than one-third of the isolates could be tentatively identified as Pseudomonas spp. which were particularly abundant in the alpine-tundra soils where they represented 60% of all isolates. Other frequently isolated Gram-negative taxa were Burkholderia sp., Collimonas sp., Pedobacter sp., Janthinobacter sp., Duganella sp., Dyella sp. and Sphingomonas sp. Growth temperature ranges and hydrolytic enzyme activities of selected ca.100 strains were screened. The strains were psychrotolerant growing generally at temperatures ranging from 0 to 30 degrees C, as 82% of the isolates grew at 0 degrees C while only 7% grew at 35 degrees C. Protease and lipase activities at 5 degrees C were detected in more than half of the strains while approximately 20% of the strains possessed amylase and/or cellulase activities.     

Prevalence of thermotolerant Campylobacter in partridges (Perdix perdix)

Aim:  To estimate the prevalence of thermotolerant Campylobacter spp. in commercially reared partridges ( Perdix perdix ) in southern Italy.
Methods and Results:  Cloacal swabs of partridges ( n  =   240), equally distributed between male and female birds, from a game bird farm located in the Southern Italy were examined for the prevalence of thermotolerant Campylobacter spp. The samples were processed in order to detect thermotolerant Campylobacter spp. by culture methods. The positive samples were then confirmed by multiplex polymerase chain reaction. Thermotolerant Campylobacter spp. were isolated from 118 (49·2%) of the 240 cloacal swabs examined. As proved by PCR, 100% of the strains were identified as Campylobacter coli (118/118), and 15 (12·7%) out of the 118 positive samples were also positive for Campylobacter jejuni . In contrast, Campylobacter lari was not identified. Adult partridges showed a significantly higher prevalence ( P  <   0·05) than younger ones.
Conclusion:  These results reinforce the assumption that game birds may be considered as potential carriers of Campylobacter spp. for human being and other animal species.
Significance and Impact of the Study:  Although an earlier 1986 publication described the prevalence of Campylobacter coli in commercially reared partridges, this is the first report to confirm the species of Campylobacter using a PCR test.     

Fungal endophytes from Acer ginnala Maxim: isolation, identification and their yield of gallic acid

Aims:  The aim of the study was to isolate the endophytic fungi from Acer ginnala and screen isolates rich in gallic acid.
Methods and Results:  After epiphytic sterilization, 145 fungal endophytes were isolated from the stem, annual twig and seed of Acer ginnala . The endophytes were grouped into ten different taxa, Phomopsis sp., Neurospora sp., Phoma sp., Epicoccum sp., Penicillium sp., Alternaria sp., Fusarium sp., Trichoderma sp., Cladosporium sp. and a species of Pleosporales Incertae Sedis , by their morphological traits and ITS-rDNA sequence analysis. The content and yield of gallic acid of 141 isolates were determined by HPLC. On average, the species of Pleosporales Incertae Sedis had the highest content and yield of gallic acid (13·28 mg g⁻¹ DW; 119·62 mg l⁻¹), while Alternaria sp. had the lowest.
Conclusions:  Of 141 fungal endophytes from A. ginnala , Phomopsis sp. isolate SX10 showed both the highest content and the highest yield of gallic acid (29·25 mg g⁻¹ DW; 200·47 mg l⁻¹).
Significance and Impact of the Study:  Endophytic fungi isolated from A. ginnala may be used as potential producers of gallic acid and other compounds with biological activities, or functioned as elicitors to produce natural compounds.     

Listeria monocytogenes in poultry and poultry products: epidemiological investigations in seven Danish abattoirs

Listeria monocytogenes was isolated from 11/236 (4·7%) caecal samples from parent flocks, providing broilers to the abattoirs investigated. Caecal samples from 2078 broilers representing 90 randomly selected broiler flocks were negative for L. monocytogenes. A total of 3080 samples from seven abattoirs including poultry processing line samples, and final products were also examined for L. monocytogenes. Listeria monocytogenes was isolated in 0·3% to 18·7% of the samples collected in the different abattoirs. Epidemiological typing of 247 L. monocytogenes isolates, including serotyping, phage typing, pulsed-field gel electrophoresis and ribotyping revealed 62 different clones. Based upon typability and discriminatory power, DNA typing methods used were found equally suitable as epidemiological markers. Serotyping and phage typing were not found useful as epidemiological markers for poultry isolates of L. monocytogenes since only 120/247 (48·6%) isolates were typable by phage typing and 230/247 (93·1%) L. monocytogenes belonged to serotype 01 while 6/247 (2·4%) belonged to 04. The discovery of a few dominating clones in each abattoir might indicate an endemic occurrence of L. monocytogenes. It is concluded that L. monocytogenes in the broiler production is primarily localized to the abattoirs. The incidence of L. monocytogenes may be reduced by improving the hygiene.     

The incidence of Bdellovibrio spp. in man-made water systems: coexistence with legionellas

Bdellovibrios have been isolated from surface waters but there are no reports of its occurrence in mains water supplies. One hundred and thirty five water samples from 81 sources were examined for the presence of Bdellovibrio bacteriovorus and Legion-ella spp. Bdellovibrics were isolated by a double-layer agar technique with two strains of Legionella pneumophila serogroup 1 as the host organisms. Bdellovibrio spp. were isolated from 57·8% and Legionella spp. from 9·5% of the samples. The two species occurred together in 4·4% of samples. The incidence of Bdellovibrio spp. and its occurrence with legionellas in man-made water systems is discussed.     

Feeding ecology and habitat preferences of the catfish genus Trichomycterus in low‐order streams of the Colombian Andes

Six lower order streams in the south‐west of Colombia were sampled on a monthly basis in order to determine the status of Trichomycterus species in relation to their food supply (macroinvertebrates), and physico‐chemical habitat. Fishes were sampled by electrofishing and samples taken for dietary analysis. Macroinvertebrates were collected using a Surber sampler. Trichomycterus spp. populations were present in all streams in habitats ranging from soft to hard substrata and from relatively stagnant waters to fast flowing streams. The average density of the fishes ranged from 0·06 to 1·14 individuals m⁻² with peaks in population corresponding to recruitment of individuals of <1 g. Trichomycterus spp. were found to be benthic carnivores with a diet mostly of aquatic insects. The index of relative importance for the dietary items was 35·0, 10·5, 1·9 and 7·8% for Chironomidae, Trichoptera, Ephemeroptera and Oligochaeta respectively. Combined with physical habitat data, ordinations of fishes and macroinvertebrate data suggested that differences in abundance among sites were driven by stream size and flow regime, indicating dominance of the physical habitat, although a high correlation between Trichomycterus spp. and Chironomidae abundances ( r  = 0·81, P  = 0·049) was also recorded.     

Filamentous Fungi Isolated from Estuarine Sediments Contaminated with Industrial Discharges

Filamentous fungi were isolated from estuarine sediments collected from two contaminated sites. One site was contaminated mainly by polycyclic aromatic hydrocarbon (PAH) with a concentration around 407?µg g^?1 of different PAHs, and the other by different sources of industrial pollutants; both were compared to a pristine site. All three sites were located in the Baixada Santista, São Paulo State, Brazil. The aim of the present investigation was the isolation of filamentous fungi from pristine and industrially polluted sediments in order to assess the mycobiota present in those sites and to evaluate their tolerance to phenanthrene and pyrene. Most of the isolated fungi were mitosporic ascomycetes, including Aspergillus sp., Chrysosporium sp., Cyclothyrium spp., Gliocladium sp., Penicillium spp., Phoma spp., and Trichoderma spp. There were also representatives of sexual Ascomycetes, Basidiomycetes, and Zygomycetes. The results showed that 59% of the evaluated fungi were tolerant to pyrene and 30% to phenanthrene. Representatives of Trichoderma were the most tolerant among the filamentous fungi investigated. A representative of Penicillium simplicissimum was the only isolate tested that had a better growth in the presence of pyrene than in its absence.     

Drinking rate, uptake of bacteria and microalgae in turbot larvae

The drinking rate of turbot larvae increased from 14 to 120 nl larva^-1 h^-1 from day 2 to 11 after hatching, which gave a slightly increased specific drinking rate (calculated per biomass) from day 2 to 7 (0·8–1·9 nl μg carbon^-1 h^-1. The clearance rate of both algae and bacteria was 10–100 times higher than the drinking rate, which indicated that the larvae had an active uptake of both algae and bacteria. On day 2 and 4 after hatching highest clearance rate was observed for Tetraselmis sp. On day 6 about the same clearance rate was observed for bacteria, Isochrysis galbana and Tetraselmis sp. Until day 4 the turbot larvae had a higher ingestion rate of Tetraselmis sp. than of I. galbana , whereas on day 6 the rates were similar (28–41 ng carbon larvae^-1 h^-1). The assimilation efficiency was somewhat higher for I. galbana than for Tetraselmis sp., and on day 6 the assimilated algae constituted 1·5 and 0·9% of the larval biomass for I. galbana and Tetraselmis sp., respectively.     

Influence of different rations and water temperatures on the growth rates of shortfinned eels and longfinned eels

Juvenile (12–152 g) shortfinned eels Anguilla australis and longfinned eels A. dieffenbachia caught in New Zealand streams were fed squid mantle Nototodarus spp. 4 days per week in laboratory experiments. A linear multiple regression equation showed the amount of food eaten (0–2·7% w day⁻¹) explained 77·7% of the variation in specific growth rates (–0·60 to +1·07% w day⁻¹) among individual eels, while previous growth rates, water temperature (10·0–20·6°C), and eel weight (12–152 g) explained a further 5·6, 1·4 and 0·8%, respectively. Growth in length ranged from –0·3 to +0·9 mm day⁻¹. Eels which were starved and then given high rations grew substantially faster than expected. Once growth rates were adjusted for differences in ration and other factors, there were no significant differences in growth rates between species or individual fish. Growth of shortfinned eels fed maximum rations of commercial eel food depended on fish size and water temperatures and ceased below 9·0°C. Growth rates in the wild were substantially less than the maximum possible, after seasonal changes in water temperatures were taken into account, indicating that food supplies and not low water temperatures were controlling growth rates in the wild.     

Nuclear abnormalities of marine fish erythrocytes

The aim of this study was to monitor erythrocyte nuclear abnormalities (NA) including micronuclei (MN) in cultured and wild sea bass Dicentrarchus labrax and wild mullet Mugil spp. Seasonal sampling was performed at seven locations along the eastern coast of the Adriatic Sea. The frequency of NA and MN was positively correlated to temperature (NA: P < 0·05, r = 0·11; MN P < 0·05, r = 0·10), and there was also a positive correlation between NA and MN frequency ( P < 0·001, r = 0·43). The lowest NA and MN values for both fish species were recorded in spring, while the highest were recorded in autumn. Significantly higher frequency of NA was seen in D. labrax compared to Mugil spp., while MN frequency was low in both species and not significantly different. There was no significant difference in NA and MN frequency between cultured and wild D. labrax sampled in the same month, and there was no difference between wild Mugil spp. sampled near or far from fish farms. In view of sampling sites, the highest values were detected in fishes from the Limski Channel, the lowest from the Janjina location.     

A two-year study of the distribution of ''thermophilic'' campylobacters in human, environmental and food samples from the Reading area with particular reference to toxin production and heat-stable serotype

The incidence of 'thermophilic' campylobacters in foods and environmental samples has been studied over a two-year period. Of 781 environmental samples, 529 (67%) were found to contain campylobacters, and campylobacters were isolated from 835 (39%) of 2116 food samples. Sewage was almost always contaminated with campylobacters (96·6% of samples) and of the food samples both poultry (55·5%) and offal (47·0%) were commonly contaminated. Determination of the heat-stable serotypes of all strains isolated from these sources and of 921 strains isolated from human faeces showed that there was a wide distribution of serotypes in most types of sample. Serotype Pen 2 was the commonest type found in human faeces (18·9%) and it was also commonest in offal (21·3%), beef (40·0%), sewage (17·7%) and was the third commonest type in poultry. A comparison of culture media and conditions for optimal production of both cytotoxic and cytotonic enterotoxins showed that Brucella Broth incubated under microaerobic conditions for 24 h at 42°C was suitable for both toxins. Detection of cytotoxic activity was most sensitive using HeLa cells. The sensitivities of two ELISA systems and a Chinese Hamster Ovary tissue culture assay for detection of cytotonic enterotoxin were comparable. Not all strains isolated from cases of enteritis in human beings produced toxin; 23·1% produced cytotonic enterotoxin and 17·5% produced cytotoxin. There was no correlation between serotype and toxin production. The wide distribution of campylobacters, indistinguishable from those isolated from cases of enteritis in human beings, leads us to conclude that simplistic statements suggesting that one particular type of food is primarily responsible for cases of human disease should not be made.     

Seasonal dynamics of invertebrate drift in a Hong Kong stream

Drift samples were taken with paired nets on 19 occasions over a 12-month period in Tai Po Kau Forest Stream (TPKFS), Hong Kong. Mean drift density (±1 S.E.) was 277·9 ± 25·0 individuals 100 m^-3; peaks in density were apparent during autumn and spring. One hundred and two taxa were recovered from the drift, and the total number of taxa drifting was positively related to water temperatures. Over 99% of the aquatic animals collected in drift samples were insects, 10 taxa of which constituted 67·3% of the entire catch. Baetid mayflies dominated the composition of the drift, comprising 40·4% of individuals caught.
Seasonal changes in the drift of individual taxa were evident, reflecting significant relationships between drift densities and water temperature: Simulium T₁ (Diptera). Anisocentropus maculatus (Trichoptera) and Amphinemura chui (Plecoptera) drifted most in winter, whereas Chimarra T₁, Polymorphanisus astictus (Trichoptera), Helodes #1 and cf. Rhantus sp. (Coleoptera) were most numerous in summer. Drifting mayflies showed spring ( Indobaetis sp., Cinygmina T₁, Serratella T₂), autumn ( Baetiella sp., Pseudocloeon T₂), or spring and autumn ( Baetis nr pseudofrequentus ) peaks which were not clearly related to water temperature. In only two cases ( A. maculatus and P. astictus ) was TPKFS drift seasonality associated with life-cycle events. Overall, there was no evidence of community-level trends in the periodicity of stream drift in this seasonal tropical habitat.     

Occurrence of Cryptosporidium and Giardia genotypes and subtypes in raw and treated water in Portugal

Aims:  Waterborne outbreaks of diarrhoeal illness reported worldwide are mostly associated with Cryptosporidium spp. and Giardia spp. Their presence in aquatic systems makes it essential to develop preventive strategies for water and food safety. This study was undertaken to monitor the presence of Cryptosporidium and Giardia in a total of 175 water samples, including raw and treated water from both surface and ground sources in Portugal.
Methods and Results:  The samples were processed according to USEPA Method 1623 for immunomagnetic separation (IMS) of Cryptosporidium oocysts and Giardia cysts, followed by detection of oocysts/cysts by immunofluorecence (IFA) microscopy, PCR-based techniques were done on all water samples collected. Out of 175 samples, 81 (46·3%) were positive for Cryptosporidium and 67 (38·3%) for Giardia by IFA. Cryptosporidium spp. and G. duodenalis genotypes were identified by PCR in 37 (21·7%) and 9 (5·1%) water samples, respectively. C. parvum was the most common species (78·9%), followed by C. hominis (13·2%), C. andersoni (5·3%), and C. muris (2·6%). Subtype IdA15 was identified in all C. hominis -positive water samples. S ubtyping revealed the presence of C. parvum subtypes IIaA15G2R1, IIaA16G2R1 and IIdA17G1. Giardia duodenalis subtype A1 was identified.
Conclusions:  The results of the present study suggest that Cryptosporidium spp. and Giardia spp. were widely distributed in source water and treated water in Portugal. Moreover, the results obtained indicate a high occurrence of human-pathogenic Cryptosporidium genotypes and subtypes in raw and treated water samples.
Significance and Impact of the Study:  Thus, water can be a potential vehicle in the transmission of cryptosporidiosis, and giardiasis of humans and animals in Portugal.     

Incidence of Listeria spp. in Breton live shellfish

Live shellfish samples (120) were collected from nine littoral sites in Brittany (western France). They were screened for Listeria spp. and a count of faecal coliforms was carried out. Analysis of the results revealed Listeria spp. in 55% of samples, a much higher rate than the previous, infrequent, recorded data. Furthermore, the study demonstrated that the frequency of Listeria spp. in winter was more important than in summer ( P < 0·001), and underlined a significant relationship between the occurrence of these bacteria and the concentration of faecal coliforms ( P < 0·001). Finally, comparison of the official and Gen-Probe^® methods revealed the limits of the standardized technique in the search for L. monocytogenes in shellfish.     

Genetic analysis of fish genomes and populations: allozyme variation within and among Atlantic salmon from Downeast rivers of Maine

Analysis of genetic variation within and among samples of naturally produced Atlantic salmon ( n  = 372) from 7 Maine (U.S.A.) and one Canadian river were conducted based on 54 allozyme loci. Eight of the 54 loci proved polymorphic, and estimated heterozygosities ( H _S) based on all loci ranged from 0·012 to 0·026 (mean = 0·021, s . e . = 0·002). Only one of 56 tests revealed genotypic proportions that deviated significantly from Hardy–Weinberg expectations. Genetic distances ( D ) between samples ranged from 0·002 to 0·022. No obvious association existed between genetic and geographic distances. Cluster analysis of genetic distances revealed the Dennys River sample as the most differentiated when all samples were included in the analysis, though bootstrap support of the cluster analysis was generally weak. G ‐tests revealed significant differences in allele frequencies among samples at five of the polymorphic loci, and the G ‐value summed over all loci also indicated significant differences among samples. F _ST values indicated that 3·4% of the total genetic diversity was due to variability among samples, while 96·6% was due to variability within samples. These results indicate that the Atlantic salmon analyzed in this study had levels of genetic variability and differentiation among samples comparable to native populations from other areas collected across a similar geographic range.     

阿特拉津降解菌株的分离和鉴定

从农药厂废水中分离到6株能以除草剂阿特拉津为唯一氮源生长的细菌,即假单胞菌（Pseudomonas spp,.)AD1,AD2和AD6,土壤杆菌（Agrobacterium sp.)AD4,黄单胞菌（Xanthomonas sp.)AD5,欧氏菌（Erwinia sp.)AD7,AD1菌株能使无机盐培养基中的0．3g/L阿特拉津在72h内降解99．9％,当以AD1,AD2,AD4,AD5,AD6和AD7菌株的总DNA为模板进行PCR扩增时,除AD2菌株以外,均得到了与献报道的假单胞菌ADP菌株的阿特拉津氯水解酶基因（atzA)同源的PCR产物。