Diversity of Salmonella spp. and fungi in northern Greek rivers and their correlation to fecal pollution indicators

The prevalence and diversity of Salmonella spp., filamentous fungi, and yeasts and their correlation with fecal pollution indicators (total coliforms, fecal coliforms, enterococci) and total heterotrophic bacteria counts were investigated in 95 water samples from the northern Greek rivers Aliakmon and Axios. Salmonella spp. were isolated in 27.4% of the samples and a total of 19 serotypes were identified. The frequency of Salmonella isolation was higher in the Axios (36.8%) than in the Aliakmon (21.0%) river. Significantly (P<0.001) more Salmonella spp. were recovered during warm (41.4%) than cold (5.4%) months. Salmonella-positive samples showed significantly higher counts of total heterotrophic bacteria and coliforms. Filamentous fungi were isolated from 98.9% and yeasts from 17.9% of the samples with respective mean counts of 2.36 x 10(3) and 1.28 x 10(2)cfu/100mL. Totals of 23 genera of filamentous fungi and 3 genera of yeasts were identified. The most frequent filamentous fungi were Penicillium and Aspergillus, while Candida was the most prevalent yeast. A significant (P<0.001) positive correlation of the fecal pollution indicators was demonstrated only for filamentous fungi. The results of this study indicate that these rivers may be potential pathways for human and other animal contamination with Salmonella spp., filamentous fungi, and yeasts, which contribute to the pollution of marine waters and the surrounding environment.     

Exposure status of East and West German households with house dust mites and fungi

The interrelation between biological pollution of indoor spaces and health disorders, allergic symptoms and health issues in general is well known. Besides animal epithelia, the exposure to house dust mites and mould fungi is considered a serious risk factor. In the scope of a comparative study involving school beginners in East and West Germany (launched in 1991), dust was vacuumed from a total of 218 mattresses of children's beds and checked for their content of house dust mites and mould fungi. This investigation aimed at assessing the degree of exposure, to determine regional differences, if any, and to uncover the correlation between exposure and symptoms. Dust mite infestation was highest in the small town of Borken in Westphalia (in 86% of the specimens > 2 micrograms mite allergens/g of dust) and lowest in Magdeburg in Saxony-Anhalt (55.3%). Total concentrations of mould fungi varied from 1.4 x 10(3) CFU/g of dust and 300 x 10(3) CFU/g of dust with a geometric mean of 26.5 x 10(3) CFU/g of dust. A total of 41 different genera/species were identified. Most frequent were the following genera: Penicillium, Eurotium, Aspergillus, Alternaria, Epicoccum and Cladosporium. The importance of individual factors influencing was confirmed. Humidity decreases the higher the flat is situated in a building. This partly explains the differences in concentrations between Borken where children live mainly on the ground floor, and the other cities with taller buildings. Spores of mould fungi were discovered more frequently in mattresses from humid flats. An association between biological indoor space factors and some allergological parameters seemed obvious, however, due to the small size of the test group most of them were not significant.     

Exposure to airborne microbial components in autumn and spring during work at Danish biofuel plants

Exposure to microbial components can cause respiratory problems. The exposure levels to microbial components at biofuel plants are not known. Therefore, exposure to inhalable airborne fungi, bacteria, actinomycetes, endotoxin and NAGase was measured using personal and stationary samplers at five Danish biofuel plants in autumn and spring. The personal exposure levels to endotoxin (median=55 EU m-3), thermophilic actinomycetes (median=1.3x10(4) colony forming units (cfu) m-3), total bacteria (median=48x10(4) cells m-3) and total fungi (median=21x10(4) spores m-3) were, in general, high at the five biofuel plants. At straw reception areas, higher exposure to most microbial components was found in spring than in autumn. Endotoxin was found in higher concentrations at straw plants than at wood-chip plants, while the opposite was measured for Aspergillus fumigatus. Some tasks were associated with exposures to microorganisms and endotoxins at much higher levels than the suggested occupational exposure limits. For example, people working with a straw shredder for at least 30 min during a working day were exposed to a median endotoxin exposure of 23,775 endotoxin units (EU) m-3. People working with estimating the water content in wood chips and repairing the chips cranes for at least 30 min during a working day were exposed to a median value of A. fumigatus of 6.7x10(4) cfu m-3 and a median value of fungi of 70x10(4) spores m-3. Consequently, this working environment may cause respiratory disorders in the people working at the plant. Differences in exposure levels were seen between the plants and this may partly be due to differences of the process equipment, tasks and the biofuel handled.     

Microbiological quality of fermented cassava flour 'kpor umilin'

A study was conducted on the microbiological quality of traditionally fermented cassava flour 'kpor umilin' and a laboratory modification of the method developed with a view to upgrading the traditional process. Microbial analysis of samples from both processing methods was evaluated using standard microbiological methods. The bacterial count in the traditionally processed flours ranged from 2.7 x 10(3) to 1.2 x 10(7) cfu/g, while the modified sample had a count of 3.5 x 10(2) cfu/g. The predominant flora were Leuconostoc spp., Lactobacillus spp., Staphylococcus spp., Micrococcus spp., Bacillus spp., Streptococcus spp. and coliforms such as Escherichia coli. Other isolates were Enterobacter spp. and proteus spp. The sample from the modified method had a negligible (4 MPN/100 ml) coliform count. The yeast and mould count ranged from 1.9 x 10(3) cfu/g to 3.9 x 10(5) cfu/g in the traditionally processed samples as compared with 1.5 x 10(3) cfu/g in the sample from the modified process. Aspergillus spp., Penicillium spp., Saccharomyces spp. and Geotrichum candidum were the predominant fungi. The poor microbiological quality of 'kpor umilin', processed traditionally, calls for urgency in upgrading the processing and preservation methods as developed in this study as well as proper education of the local processors on good manufacturing practices.     

Prospective survey of indoor fungal contamination in hospital during a period of building construction

An 18-month survey of indoor fungal contamination was conducted in one haematology unit during a period of construction work. Air was sampled with a portable Air System Impactor and surfaces with contact Sabouraud plates. During this survey the mean concentration of viable fungi in air was 4.2 cfu/m(3) and that for surfaces was 1.7 cfu/plate. At the beginning of construction work, there were increases in airborne fungal spores (from 3.0 to 9.8 cfu/m(3)) in the unit, but concentrations did not exceed 10 cfu/m(3) during the 18-month period. The most frequently recovered airborne fungi were Penicillium spp. (27-38%), Aspergillus spp. (25%) and Bjerkandera adusta, a basidiomycete identified with molecular tools (7-12%). Blastomycetes accounted for more than 50% of the fungal flora on surfaces. Investigating the impact of a new air-treatment system (mobile Plasmair units), there were significant reductions in fungal contamination for the Plasmer -treated rooms, and in these rooms we observed the same level of fungal load whether construction work was in progress or not.     

A 2‐year survey of the airborne mycoflora in a hospital environment

Studies on levels of airborne fungal spores in hospital wards and a diet kitchen were carried out for a period of 24 months using an air sampler. In a preliminary study using Sabouraud dextrose agar (SDA), SDA with chloramphenicol, acidified malt extract agar, oxytetracycline glucose yeast extract and Rose‐Bengal chloamphenicol varying levels of fungi were recovered on each of these media. Sabouraud medium, which is used to recover medically important fungi, showed relatively lower fungal counts with an average of 89 cfu m^‐3 as compared with counts > 210 cfu m^‐3 on all the other media. Fungi accounted for about 68% of the total viable counts and the predominant genera were Aspergillus, Fusarium, Monilia, Penicillium, Rhizopus, Monilia, Candida, Rhodotorula and Pichia. Spore counts were higher in the wards (303 cfu m^‐3) than in the diet kitchen (208 cfu m^‐3) The aerial fungal spore counts were 51% higher in all the areas sampled during the warmer months than the colder months but there was no major change in the types of fungi except that Chrysonilia species were only isolated between October and March when they accounted for < 5% of the total fungal isolates.     

Seasonal variability of culturable fungal genera in the house dust of inner-city residences

House dust samples were collected up to six times over a 1-year period to explore seasonal variability of individual fungal genera in inner-city households in Minneapolis, Minnesota. General linear mixed-effects models were used to explore the variability of 13 fungal genera (Cladosporium, yeasts, Aureobasidium, Alternaria, Penicillium, Epicoccum, Mucor, Rhodotorula, Aspergillus, sterile fungi, Phoma, Pithomyces, and Fusarium) found in more than 20% of total dust samples. The five most common fungi (% of samples detected) were Cladosporium (81%), yeasts (63%), Aureobasidium (57%), Alternaria (56%), and Penicillium (55%), with the remaining genera found in 20-50% of the samples. When expressed as frequency of occurrence (%), genus fraction of total fungal concentration (%), or concentration of individual genera (CFU/g), these five genera also varied substantially by season. In contrast, Aureobasidium, Fusarium, and Mucor levels remained relatively constant throughout the year. The observed concentrations of the five most common fungal genera were higher than levels associated with increased respiratory symptoms reported in previous studies. Our results indicate that seasonal variability in common fungal genera is large: within-home to between-home variance ratios of Penicillium (4.1), Alternaria (4.9), Cladosporium (7.1), and yeasts (20.3) were substantially larger than that observed for total fungi (2.5). These results suggest that future studies attempting to link individual fungal genera to health effects need to characterize and control for this seasonal variability.     

Fungal contamination in hospital environments.

OBJECTIVES: To assess the degree of fungal contamination in hospital environments and to evaluate the ability of air conditioning systems to reduce such contamination. METHODS: We monitored airborne microbial concentrations in various environments in 10 hospitals equipped with air conditioning. Sampling was performed with a portable Surface Air System impactor with replicate organism detection and counting plates containing a fungus-selective medium. The total fungal concentration was determined 72-120 hours after sampling. The genera most involved in infection were identified by macroscopic and microscopic observation. RESULTS: The mean concentration of airborne fungi in the set of environments examined was 19 +/- 19 colony-forming units (cfu) per cubic meter. Analysis of the fungal concentration in the different types of environments revealed different levels of contamination: the lowest mean values (12 +/- 14 cfu/m(3)) were recorded in operating theaters, and the highest (45 +/- 37 cfu/m(3)) were recorded in kitchens. Analyses revealed statistically significant differences between median values for the various environments. The fungal genus most commonly encountered was Penicillium, which, in kitchens, displayed the highest mean airborne concentration (8 +/- 2.4 cfu/m(3)). The percentage (35%) of Aspergillus documented in the wards was higher than that in any of the other environments monitored. CONCLUSIONS: The fungal concentrations recorded in the present study are comparable to those recorded in other studies conducted in hospital environments and are considerably lower than those seen in other indoor environments that are not air conditioned. These findings demonstrate the effectiveness of air-handling systems in reducing fungal contamination.     

Aspergillus surveillance project at a large tertiary-care hospital

A one-year surveillance project was conducted at a large tertiary hospital, which had extensive indoor renovation and extensive demolition/building at several nearby sites. This study collected viable fungi samples in the hospital every six days and analysed 74 duct dust samples for Aspergillus fumigatus mycelial asp f1 protein. Mean total fungi were 257.8 cfu/m3 outdoors, 53.2 cfu/m3 in all indoor samples and 83.5 cfu/m3 in the bone marrow transplant patient rooms. Mean total aspergillus was 6.8 cfu/m3 outdoors, 12.1 cfu/m3 in all indoor samples and 7.3 cfu/m3 in the bone marrow transplant patient rooms. The five most prevalent Aspergillus species collected inside the hospital (mean cfu/m3) were Aspergillus niger 7.57 cfu/m3, Aspergillus candidus 1.72 cfu/m3, Aspergillus flavus 0.97 cfu/m3, A. fumigatus 0.88 cfu/m3 and Aspergillus glaucus 0.45 cfu/m3. In rooms undergoing duct cleaning, mean A. fumigatus concentrations were 11.0 cfu/m3. Forty-eight of 74 (65%) duct dust samples had measurable levels of asp f1 protein, with a mean level of 0.41 ppm and maximum level of 1.94 ppm. Three major incidents involved increased hospital aspergillus concentrations. A. niger levels reached 680 cfu/m3 in an organ transplant room after a water leak from a ceiling pipe. Total aspergillus concentrations rose to 77 cfu/m3 in a bone marrow transplant patient room after improper sealing and water infiltration of the unit's dedicated high-efficiency particulate air filter system. Total aspergillus levels of 160 cfu/m3 were recorded in a renovation area during wood cutting. The higher concentrations of aspergillus seen inside the hospital compared with outdoors and the various moisture/HEPA filter/renovation incidents suggest that numerous small to moderate sources of aspergillus exist in the hospital.     

An indoor bio-contaminants air quality

Both the quantity and quality of microorganisms (mold, actinomycetes and bacteria) were investigated in the air of five clean rooms indoors, outdoor air sampling was a routine work of the present study. Total viable bacterial counts were recorded in a mean value of 103 cfu/m3, whereas mold counts ranged between 102-103 cfu/m3. The highest mold counts were recorded at some places investigated such as research laboratories and a library. Moreover, the types, percentages and frequencies of occurance of viable mold were studied. Penicillium, Cladosporium and Aspergillus were the predominant mold genera. These organisms are aeroallergens. Actinomycetes were detected in low numbers compared with other organisms (range between 0-102 cfu/m3). Yellow, grey and white colour series were dominant streptomycetes. The mold and streptomycetes spore sizes were measured microscopically. The sizes of major mold spores ranged between 2.5-10 mum, whereas that of streptomycetes spores ranged between 1.2-2.5 mum. The particles < 5 mum in sizes are likely to reach the alveoli which may elicit potential risk for exposed residents. However, a low number of air microorganisms does not mean a clean and healthy environment.     

Filamentous fungi in a tertiary care hospital: environmental surveillance and susceptibility to antifungal drugs.

OBJECTIVE: To evaluate filamentous fungi with respect to environmental load and potential drug resistance in a tertiary care teaching hospital. DESIGN: Monthly survey in 2 buildings of the hospital during a 12-month period. SETTING: Hippokration Hospital in Thessaloniki, Greece. METHODS: Air, surface, and tap water sampling was performed in 4 departments with high-risk patients. As sampling sites, the solid-organ transplantation department and the hematology department (in the older building) and the pediatric oncology department and the pediatric intensive care unit (in the newer building) were selected. RESULTS: From January to May of 2000, the fungal load in air (FLA) was low, ranging from 0 to 12 colony-forming units (cfu) per m(3) in both buildings. During the summer months, when high temperature and humidity predominate, the FLA increased to 4-56 cfu/m(3). The fungi commonly recovered from culture of air specimens were Aspergillus niger (25.9%), Aspergillus flavus (17.7%), and Aspergillus fumigatus (12.4%). Non-Aspergillus filamentous fungi, such as Zygomycetes and Dematiaceous species, were also recovered. The pediatric intensive care unit had the lowest mean FLA (7.7 cfu/m(3)), compared with the pediatric oncology department (8.7 cfu/m(3)), the solid-organ transplantation department (16.1 cfu/m(3)), and the hematology department (22.6 cfu/m(3)). Environmental surfaces were swabbed, and 62.7% of the swab samples cultured yielded filamentous fungi similar to the fungi recovered from air but with low numbers of colony-forming units. Despite vigorous sampling, culture of tap water yielded no fungi. The increase in FLA observed during the summer coincided with renovation in the building that housed the solid-organ transplantation and hematology departments. All 54 Aspergillus air isolates randomly selected exhibited relatively low minimum inhibitory or effective concentrations for amphotericin B, itraconazole, voriconazole, posaconazole, micafungin, and anidulafungin. CONCLUSION: Air and surface fungal loads may vary in different departments of the same hospital, especially during months when the temperature and humidity are high. Environmental Aspergillus isolates are characterized by lack of resistance to clinically important antifungal agents.     

Exposure level and distribution characteristics of airborne bacteria and fungi in Seoul metropolitan subway stations

The exposure level and distribution characteristics of airborne bacteria and fungi were assessed in the workers' activity areas (station office, bedroom, ticket office and driver's seat) and passengers' activity areas (station precinct, inside the passenger carriage, and platform) of the Seoul metropolitan subway. Among investigated areas, the levels of airborne bacteria and fungi in the workers' bedroom and station precincts were relatively high. No significant difference was found in the concentration of airborne bacteria and fungi between the underground and above ground activity areas of the subway. The genera identified in all subway activity areas with a 5% or greater detection rate were Staphylococcus, Micrococcus, Bacillus and Corynebacterium for airborne bacteria and Penicillium, Cladosporium, Chrysosporium, Aspergillus for airborne fungi. Staphylococcus and Micrococcus comprised over 50% of the total airborne bacteria and Penicillium and Cladosporium comprised over 60% of the total airborne fungi, thus these four genera are the predominant genera in the subway station.     

Microbiological quality of muesli samples purchased in retail network

The estimation of microbiological quality of muesli samples was the aim of this investigation. The study included 40 samples which represented various consignments of muesli, produced in 2002 year. Total number of aerobic mesophilic bacteria, yeasts and moulds, and also occurrence of pathogenic bacteria, coliforms and enterococci were determined. The systematic units of muesli fungal flora have been identified. It was stated that microbiological quality of all tested muesli was good. No pathogenic bacteria (Salmonella, Staphylococcus aureus and Bacillus cereus) was detected and also coliforms and enterococci titre was correct (> 0.1 g). A majority of samples characterized low contamination levels of mesophilic aerobic bacteria and fungi, and their total number did not exceed, suitably 10(3) and 10(2) cfu/g. The mesophilic aerobic bacteria were mainly represented by vegetative forms. The average share of these bacteria spores in total number of bacteria received 30%. The Aspergillus sp. and Penicillium sp. were regular elements of muesli fungal flora.     

Airborne microbial contents in two types of swine confinement buildings in Quebec

Airborne microorganisms were isolated with a sampler in two types of swine confinement buildings (farrowing units and fattening units). Respirable (particles less than 5 microns) and total dust fractions were obtained. Samplings were repeated every 2 weeks for a total of 6 samplings per unit between January and April. The predominant microorganisms isolated were bacteria (up to 1.25 x 10(6) CFU/m3) with an important fraction in the respirable size range (up to 0.5 x 10(6) CFU/m3). Only small quantities of gram-negative bacteria, yeasts, and molds were found. Identification of the colonies isolated revealed a great diversity of microorganisms present in the air of the different buildings. Enterobacter agglomerans, Moraxella, Acinetobacter calcoaceticus, and Pseudomonas were the most frequently identified bacteria. Scopulariopsis, Aspergillus, Penicillium, and Candida were the most numerous fungi. Faenia rectivirgula, the causative agent of farmer's lung, was not a major contaminant. The results show some differences in airborne microbial contamination between farrowing and fattening units; the distinction, however, is not clear-cut and was observed only for the total bacteria. The level of airborne microbial contamination in swine units does not significantly vary as a function of the outside temperature. Some species of bacteria and fungi isolated in this study are known to induce extrinsic allergic alveolitis. Other fungi are known to be potentially pathogenic for man. The air of swine confinement buildings is highly contaminated with bacteria, yeasts, and molds at a level up to 1200 time higher than so-called "normal air."     

Correlation between the prevalence of certain fungi and sick building syndrome

OBJECTIVE: To examine the role of fungi in the production of sick building syndrome. METHODS: A 22 month study in the United States of 48 schools (in which there had been concerns about health and indoor air quality (IAQ). Building indoor air and surface samples, as well as outdoor air samples were taken at all sites to look for the presence of fungi or their viable propagules. RESULTS: Five fungal genera were consistently found in the outdoor air and comprised over 95% of the outdoor fungi. These genera were Cladosporium (81.5%), Penicillium (5.2%), Chrysosporium (4.9%), Alternaria (2.8%), and Aspergillus (1.1%). At 20 schools, there were significantly more colony forming units per cubic metre (CFU/m3) (p < 0.0001) of propagules of Penicillium species in the air samples from complaint areas when compared with the outdoor air samples and the indoor air samples from noncomplaint areas. At five schools, there were more, although not significant (p = 0.10), Penicillium propagules in the air samples from complaint areas when compared with the outdoor air samples and the indoor air samples from noncomplaint areas. In 11 schools, the indoor air (complaint areas) fungal ratios were similar to that in the outdoor air. In these 11 schools Stachybotrys atra was isolated from swab samples of visible growth under wetted carpets, on wetted walls, or behind vinyl wall coverings. In the remaining 11 schools, the fungal ratios and CFU/m3 of air were not significantly different in different areas. Many of the schools took remedial action that resulted in an indoor air fungal profile that was similar to that outdoors. CONCLUSIONS: Propagules of Penicillium and Stachybotrys species may be associated with sick building syndrome.

 

     

Characterization of exposure to molds and actinomycetes in agricultural dusts by scanning electron microscopy, fluorescence microscopy and the culture method

Air samples from 79 farms with 10(5) to 10(11) microorganisms/m3 were analyzed by scanning electron microscopy (SEM), fluorescence microscopy (FM), and the culture method. The total exposure to microorganisms (particularly actinomycetes) was underestimated when assessed as colony-forming units (cfu). The average cfu count was one-sixth of the total count according to SEM or FM, and the individual variability was great. This occurrence was partly explained by the aggregation of spores. Single spores accounted for 2-65% of all spores in 35 samples. There was an average of three spores/particle, and 93 (range 67-100)% of the spores were single or in aggregates of respirable size. Aggregation was more pronounced for actinomycetes and at high spore counts. Actinomycetes and bacteria could not be distinguished by FM. Bacteria (other than actinomycetes) were not detected by SEM, yet the total count of microorganisms was similar for FM and SEM. Most particles were spores from actinomycetes and fungi of the genera Aspergillus or Penicillium.     

Volatile metabolites produced by three strains of Stachybotrys chartarum cultivated on rice and gypsum board

Stachybotrys chartarum (atra) is a toxigenic fungus frequently found in water-damaged buildings. Although microbial volatile organic compounds (MVOCs) produced by Aspergillus, Penicillium, and other fungi have been investigated extensively, little information exists on what MVOCs can be produced by S. chartarum. In this study, three strains of S. chartarum isolated from water-damaged residential homes in Cleveland, Ohio, were cultivated on rice and gypsum board. Air samples were collected after one, two, three, four, and six weeks of cultivation using Tenax TA tubes. Unique MVOCs were determined and other alcohols, ketones, and terpenes were also investigated using gas chromatography/mass spectrometry after thermal desorption from the sampling tube. Four unique MVOCs, 1-butanol, 3-methyl-1-butanol, 3-methyl-2-butanol, and thujopsene, were detected on rice cultures, and only one of them (1-butanol) was detected on gypsum board cultures. For a given strain, volatiles were considerably different with different cultivation media. Concentration profiles of the volatile compounds varied among compounds; however, each compound exhibited corresponding concentration trends between the strains. In comparison with our previous studies of five Aspergillus species on gypsum board under the same experimental conditions, fewer unique MVOCs were produced by S. chartarum, and they were quite different. It thus may be possible to use marker-unique MVOCs as a fingerprint to distinguish fungi in indoor environments once enough information becomes available. Our findings also indicate that volatiles produced by S. chartarum may represent a relatively small fraction of the total volatiles present in problem buildings where Aspergillus spp., Penicillium spp., and other fungi usually coexist.     

重庆市城区空气微生物污染及评价

目的：了解重庆市城区空气微生物污染状况，方法：1999年11月13日－12月13日在重庆市城区某采样点距地面1．5m高度采空气样，每天3次，连续30d，采用中国科学院生态中心推荐使用的空气微生物评价标准评价空气微生物污染状况，结果：空气细菌和霉菌计数分别为76－21758cfu/m^3和1538－4179cfu/m^3，分别占空气微生物总数的63．8％和36．2％，霉菌包括马丁霉菌（20．4％）和耐高渗透压霉菌（15．8％），细菌、马丁霉菌和耐高压霉菌的优势菌株分别为芽孢杆菌（52．4％），曲霉菌（19．0％），和青霉菌（32．6％），细菌中97．1％和G＋，空气样本中细菌、马丁霉菌和耐高渗透压霉菌含量达污染级别及以上的分别为45．6％，72．1％和63．3％，结论：重庆市城区空气微生物污染较重，尤其是空气霉菌的污染应引起重视。     

Bioaerosol exposure in waste collection: A comparative study on the significance of collection equipment,type of waste and seasonal variation

Recent Danish studies on waste collectors' bioaerosol exposure are summarized. Generally the median exposure levels ranged from 10⁵ to 10⁶ cells m⁻³ (total microorganisms), 10⁴ to 10⁵ cfu m⁻³ (culturable fungi) and 10³ to 10⁴ cfu m⁻³ (culturable bacteria). The type of waste was a governing factor for exposure. Garden waste collectors frequently experienced concentrations exceeding 10⁵ cfu m⁻³ for mesophilic fungi and 10⁴ cfu m⁻³ for the thermophilic fungus Aspergillus fumigatus. Workers collecting compostable, mixed and sorted waste occasionally experienced similar concentrations of the fungal groups while workers collecting ‘bulky waste’ and paper had low exposure. Type of collection vehicle was identified as another governing factor for exposure. Vehicles loaded from the top (approximately 3 m above the ground) caused lower exposure (by a factor of 25) to fungi than vehicles loaded at the level or the breathing zone of the workers. Exposure was also affected by season of the year—the concentration of total microorganisms, culturable fungi, Aspergillus fumigatus and endotoxin was low in winter. Exposure to total microorganisms counted by microscopy was found to have a fairly high validity (Va) as an indicator of exposure to culturable fungi (Va = 1.45) or culturable bacteria (Va = 1.25). Likewise, dust may also be used as an indicator of exposure to total microorganisms (Va= 1.36), culturable fungi (Va= 1.31) and culturable bacteria (Va = 1.35).     

Microbiologic evaluation of instant soup concentrates

The microbiological condition of instant soup powders purchased in retail network has been assessed. The study included 37 instant soups (8 types) manufactured by four Polish companies. The microbiological quality of a majority of soup powders fulfilled the requirements of the standard. No pathogenic bacteria (Salmonella, E. coli and Staphylococcus aureus) were detected, nor were there any spores of sulphitereducing anaerobic bacteria found. However, some samples of powders, mainly from one manufacturer, did have an excessive total number of bacteria (> 10(5) cfu/g) and a reduced (down to 0.01 g) level of coliform count. Aerobic bacteria occurring in powders were of vegetative and spore forms and exhibited the activity of amylo-, lipo- and proteolytic exoenzymes. The quantity of moulds did not exceed 100 cfu/g in a majority of samples. They were mainly represented by Penicillium sp., Aspergillus sp., Alternaria sp. and Cladosporium sp.