Production of patulin and citrinin by Penicillium expansum from British Columbia (Canada) apples.

Twenty-four isolates of Penicillium expansum Link from British Columbia (Canada) apples were cultured in yeast-extract sucrose (YES) at 25°C for 28 days to investigate production of patulin and citrinin. These isolates proved to be potent producers of citrinin, patulin, or in most cases, both mycotoxins. In every isolate, citrinin, patulin, or both compounds were produced at levels as high as 565 µg/mL (mean 269 µg/mL) and 100 µg/mL (mean 31 µg/mL), respectively. Of the 24 isolates, 4 produced citrinin only, and 2 produced patulin only. Overall, 83% of the isolates formed patulin and 91% formed citrinin. YES broth proved to be an effective medium for patulin and citrinin production. Other workers have noted that production of these mycotoxins in culture often presages production in fruits, so these results might help Canadian fruit processors evaluate and minimize mycotoxin levels in their products.

Mycotoxins in breakfast cereals from the Canadian retail market: a 3-year survey.

One hundred and fifty-six samples of breakfast cereals were collected from the Canadian retail marketplace over a 3-year period. The samples were analysed for the mycotoxins deoxynivalenol, nivalenol, HT-2 toxin, zearalenone, ochratoxin A, and fumonisins B1 and B2 to contribute to dietary exposure estimates in support of the development of Canadian guidelines for selected mycotoxins in foods. The samples included corn-, oat-, wheat- and rice-based cereals, as well as mixed-grain cereals, and were primarily from North American processors. Overall, deoxynivalenol was the most frequently detected mycotoxin--it was detected in over 40% of all samples analysed. Fumonisins and ochratoxin A were each detected in over 30% of all samples. Zearalenone was detected in over 20% of all samples. Nivalenol and HT-2 toxin were each detected in only one sample. The survey clearly demonstrated regular occurrence of low levels of multiple mycotoxins in breakfast cereals on the Canadian market.

Determination of ochratoxin A in green coffee by immunoaffinity column cleanup and liquid chomatography: collaborative study.

A collaborative study was conducted to evaluate a method using immunoaffinity column cleanup with liquid chromatography (LC) for the determination of ochratoxin A (OTA) in green coffee at levels that could be included in possible future regulations of the European Union. The test portion was extracted with methanol-3% aqueous sodium hydrogen carbonate solution (50 + 50, v/v). The extract was filtered, and the filtrate was diluted with phosphate-buffered saline and applied to an immunoaffinity column containing antibodies specific for OTA. After washing, the toxin was eluted from the column with methanol and quantified by LC with fluorescence detection. Pairs of 4 homogeneous noncontaminated and naturally contaminated materials (mean levels of < 0.12, 2.44, 5.15, and 13.46 ng/g) and blank samples (< 0.12 ng/g) for spiking were sent to 20 participant laboratories from 8 countries. The materials were analyzed according to the method description and all difficulties encountered in the analysis were reported. Statistical analysis was carried out according to the Harmonized Protocol of the International Union of Pure and Applied Chemistry. The relative standard deviation for repeatability (RSDr) ranged from 7.42 to 20.94%, and the relative standard deviation for reproducibility (RSDR) ranged from 16.34 to 29.17%. The method showed acceptable within-laboratory and between-laboratories precision for green coffee materials, as evidenced by HorRat values of < or = 0.85, at the studied range, for spiked and naturally contaminated materials. The mean recovery was 92.8% for green coffee material spiked with OTA at a level of 4.82 ng/g.

Stachybotrys chartarum alters surfactant-related phospholipid synthesis and CTP:cholinephosphate cytidylyltransferase activity in isolated fetal rat type II cells.

Stachybotry chartarum, a fungal contaminant of water-damaged buildings commonly grows on damp cellulose-containing materials. It produces a complex array of mycotoxins. Their mechanisms of action on the pulmonary system are not entirely clear. Previous studies suggest spore products may depress formation of disaturated phosphatidylcholine (DSPC), the major surface-active component of pulmonary surfactant (PS). If S. chartarum can indeed affect formation of this phospholipid, then mold exposure may be a significant issue for pulmonary function in both mature lung and developing fetal lung. To address this possibility, fetal rat type II cells, the principal source of DSPC, were used to assess effects of S. chartarum extract on formation of DSPC. Isolated fetal rat lung type II cells prelabeled with 3H-choline and incubated with spore extract showed decreased incorporation of 3H-choline into DSPC. The activity of CTP:cholinephosphate cytidylyltransferase (CPCT), the rate-limiting enzyme in phosphatidylcholine synthesis was reduced by approximately 50% by a 1:10 dilution of spore extract. Two different S. chartarum extracts (isolates from S. chartarum (Cleveland) and S. chartarum (Hawaiian)) were used to compare activity of CPCT in the presence of phosphatidylglycerol (PG), a known activator. PG produced an approximate two-fold increase in CPCT activity. The spore isolate from Hawaii did not alter enzyme activity. S. chartarum (Cleveland) eliminated the PG-induced activation of CPCT. These results support previous observations that mold products alter PS metabolism and may pose a risk in developing lung, inhibiting surfactant synthesis. Different isolates of the same species of fungus are not equivalent in terms of potential exposure risks.

Ochratoxin A in dried vine fruits on the Canadian retail market.

Between 1998 and 2000, 151 samples of raisins and sultanas and two samples of currants were collected from retail outlets across Canada and analysed for ochratoxin A. Samples were extracted with methanol-sodium bicarbonate, and the extracts were cleaned-up by immunoaffinity column chromatography. Ochratoxin A was quantified by liquid chromatography with fluorescence detection. The minimum quantifiable level was 0.1 ng (g-1). Ochratoxin A was present, above the minimum quantifiable level, in 67 (79%) of 85 samples of raisins, in 39 (59%) of 66 samples of sultanas, and in both samples of currants. The overall mean level of ochratoxin A was 1.8 ng g(-1) in both the raisins and sultanas, and 2.8 ng g(-1) in the currants.

Mycotoxins in infant cereal foods from the Canadian retail market.

Three hundred and sixty-three samples of cereal-based infant foods were collected from the Canadian retail marketplace over 3 years. The samples included oat-, barley-, soy-, and rice-based infant cereals, mixed-grain infant cereals, teething biscuits, creamed corn, and soy-based formulas. Samples were analysed for targeted mycotoxins (deoxynivalenol, nivalenol, HT-2 toxin, zearalenone, ochratoxin A, fumonisins B(1) and B(2), and five ergot alkaloids). Soy-based cereals (which usually contain corn) exhibited the highest incidences of deoxynivalenol (100%), zearalenone (46%) and fumonisins (75%). Overall, deoxynivalenol was the most frequently detected mycotoxin--it was detected in 63% of samples analysed. Survey results demonstrated the regular occurrence of multiple mycotoxins in cereal-based infant foods.

Survey of Canadian retail coffees for ochratoxin A.

One-hundred and one specimens of coffee were gathered from retail outlets across Canada and analysed for ochratoxin A. Seventy-one specimens were roasted beans or roasted ground coffee, and 30 were instant (or 'soluble') coffees. All samples were extracted with methanol-sodium bicarbonate. The extracts were cleaned up either by immunoaffinity column chromatography or by a combination of solid-phase extraction and immunoaffinity column chromatography. Ochratoxin A was quantified by liquid chromatography (LC) with fluorescence detection. The minimum quantifiable level was 0.1 ng g(-1). Ochratoxin A was present, above the minimum quantifiable level, in 42 (59%) of 71 beans and ground coffee and in 20 (67%) of 30 instant coffees. The mean ochratoxin A level in the positive samples of beans and ground coffee was 0.6 ng g(-1), and the mean level in the positive samples of instant coffee was 1.1 ng g(-1).

An efficient formulation of Krylov's prediction model for train induced vibrations based on the dynamic reciprocity theorem.

In Krylov's analytical prediction model, the free field vibration response during the passage of a train is written as the superposition of the effect of all sleeper forces, using Lamb's approximate solution for the Green's function of a halfspace. When this formulation is extended with the Green's functions of a layered soil, considerable computational effort is required if these Green's functions are needed in a wide range of source-receiver distances and frequencies. It is demonstrated in this paper how the free field response can alternatively be computed, using the dynamic reciprocity theorem, applied to moving loads. The formulation is based on the response of the soil due to the moving load distribution for a single axle load. The equations are written in the wave-number-frequency domain, accounting for the invariance of the geometry in the direction of the track. The approach allows for a very efficient calculation of the free field vibration response, distinguishing the quasistatic contribution from the effect of the sleeper passage frequency and its higher harmonics. The methodology is validated by means of in situ vibration measurements during the passage of a Thalys high-speed train on the track between Brussels and Paris. It is shown that the model has good predictive capabilities in the near field at low and high frequencies, but underestimates the response in the midfrequency band.

Furanocoumarins in celery and parsnips: method and multiyear Canadian survey.

The natural occurrence of biologically active furanocoumarins in common vegetables is an area of increasing interest with respect to human health. In this study, an efficient, rugged, and sensitive liquid chromatographic method with ultraviolet photodiode array detection was developed for the estimation of 5 biologically active furanocoumarins (psoralen, bergapten, xanthotoxin, trioxsalen, and angelicin) in celery and parsnips. When authentic samples were spiked with a mixture of furanocoumarins at individual levels of 2 to 10 microg/g, the method produced overall recoveries of 77 and 75% of all furanocoumarins from celery and parsnips, respectively. The method was applied in 2 laboratories to a multiyear survey of more than 200 samples. Of 110 parsnips samples, 109 (99%) contained quantitatable levels of furanocoumarins. The mean level of total furanocoumarins in the positive parsnip samples was 15.1 microg/g; the maximum level detected was 145 microg/g. Of 114 celery samples, 88 (77%) contained quantitatable levels of furanocoumarins. The mean level of total furanocoumarins in the positive celery samples was 1.9 microg/g; the maximum level detected was 15.2 microg/g. Xanthotoxin and bergapten were the most commonly detected furanocoumarins in both celery (68 and 63%) and parsnips (97 and 96%). Xanthotoxin had the highest mean level of positives in both celery (1.3 microg/g) and parsnips (8.5 microg/g). Little year-to-year variation in either total furanocoumarin levels or incidence was noted.

A comparison of clinical, histopathological and cell-cycle markers in rats receiving the fungal toxins fumonisin B1 or fumonisin B2 by intraperitoneal injection.

Fumonisins B1 and B2 (FB1 and FB2) are fungal secondary metabolites produced by members of the genus Fusarium. Although FB1 is usually detected in greater quantities, FB2 frequently co-occurs in contaminated feeds and foods and contributes to the total toxin load. In the present study, the comparative toxicity of FB1 and FB2 was examined in male Sprague-Dawley rats administered toxin (0.75 mg/kg body weight) or vehicle control intraperitoneally (ip) for 2, 4 or 6 consecutive days. Clinical changes, including elevated serum cholesterol, alanine aminotransferase (ALT), creatinine and protein, were slightly more pronounced in FB1-treated rats. The most consistent hematological change was an increase in vacuolated bone marrow cells, which was more pronounced in FB1-treated rats. Histopathological changes were similar in FB1- and FB2-treated rats and included single cell necrosis in kidneys and liver, cytoplasmic vacuolation in adrenal cortex and lymphocytolysis in thymus. In the liver mRNA expression for the cyclin kinase inhibitor p21 gene was significantly increased in FB1- and FB2-treated rats, compared to controls. Expression of mRNA for the cyclin D1 gene was significantly depressed in FB2-treated rats. Hepatic cyclin E mRNA was elevated in response to FB1 and FB2 compared to controls. In FB2-treated animals this corresponded with decreased liver p27 mRNA expression. Hepatic proliferating cell nuclear antigen (PCNA) transcription was elevated in FB1- but not FB2- treated rats. Changes in liver microsomal protein levels of p27, cyclin E and PCNA were similar to changes in gene expression. In contrast, cyclin D1 protein levels were elevated in rats treated with FB1 and, to a lesser extent, FB2. The data indicate that FB1 and FB2 can alter the expression of genes associated with the cell cycle, and indicate a need for a further understanding of the mechanistic basis of FB1 and FB2 toxicity.

Cost-effectiveness analysis of pneumococcal vaccination of adults and elderly persons in Belgium.

OBJECTIVE: To analyse the direct medical costs and effectiveness of vaccinating adults aged between 18 and 64 years and elderly persons > or = 65 years of age with the 23-valent pneumococcal polysaccharide vaccine. DESIGN AND SETTING: This was a decision-analytic modelling study from the societal perspective in Belgium. The analysis compared 'vaccination' with 'no vaccination and treatment'. METHODS: Calculations were based on the assumption that vaccination is as effective against all pneumococcal infections as it is against invasive pneumococcal disease. Data on the incidence of pneumococcal pneumonia and meningitis, frequency of hospitalisation, mortality rates and vaccine effectiveness were derived from the international literature. Costs were derived from analysis of historical data for cases of pneumococcal infection in Belgium. RESULTS: Vaccinating 1000 adults between the ages of 18 and 64 years gains approximately 2 life-years in comparison with the no vaccination option. However, to realise these additional health benefits requires additional costs of 11,800 European Currency Units (ECU; 1995 values) per life-year saved. Vaccinating 1000 elderly people (> or = 65 years) leads to > 9 life-years gained as well as a small monetary benefit of ECU1250. An extensive sensitivity analysis did not greatly affect the results for the elderly population: vaccination in this age group always remained favourable, and thus it is clearly indicated from an economic point of view. A crucial assumption for both age groups is that the effectiveness of the vaccine holds for all pneumococcal pneumonia. It is clear that the results will become less favourable if this assumption is dropped. CONCLUSIONS: Preventing pneumococcal infections by vaccination clearly benefits people's health. Reimbursement can be recommended for the elderly group; however, more accurate epidemiological data are still needed to make decisions concerning routine pneumococcal vaccination in adults < 65 years of age. Unfortunately, the issue of whether the effectiveness of the vaccine holds for all pneumococcal pneumonia is as yet unresolved in the medical literature.

Studies on extraction of fumonisins from rice, corn-based foods and beans.

Different solvent mixtures were examined for extraction of fumonisins from various naturally contaminated and spiked foods and foodstuffs: rough rice, retail rice, rice flour, white corn flour, corn meal, corn starch, corn flakes, tortilla/corn chips, white bean flour, white beans, mung beans, adzuki beans and infant cereals. Most of the naturally contaminated samples were analyzed using the extraction solvent mixtures methanol-acetonitrile-water (25:25:50) (solvent A) and methanol-water (75:25 or 80:20) (solvents B, BB); some were extracted with 0.1 M sodium hydrogen phosphate-acetonitrile (1:1, adjusted to pH 3.0 with o-phosphoric acid) (solvent C) and methanol-0.025 M borate buffer (3:1, adjusted to pH 9.2 with 1 N sodium hydroxide) (solvent D). A 1-ml SAX solid phase extraction column was used for the cleanup in all cases except for infant cereals, for which immunoaffinity chromatography was used; fumonisin concentrations were determined by liquid chromatography.Solvent A gave slightly better extraction of fumonisins from one of two samples of naturally contaminated rough rice than solvent B (fumonisin B1: 4080 ng/g versus 3150 ng/g; fumonisin B2:1100 ng/ g versus 922 ng/g) and much better extraction than solvent C (1210 ng/g fumonisin B1 and 315 ng/g fumonisin B2) or solvent D (372 ng/ g fumonisin B1 and 191 ng/g fumonisin B2). However, spike recoveries on a similar rice naturally contaminated at a lower level were only in the 43-53% range (solvent A). Recovery of fumonisins was very poor from spiked white rice flour but satisfactory from other rice foods.Solvent A similarly gave slightly better extraction of fumonisins from a sample of naturally contaminated white corn flour than solvent B (fumonisin B1 1260 ng/g versus 931 ng/g; fumonisin B2: 511 ng/g versus 447 ng/g ) and better extraction than solvents C and D. Solvent A was also a better solvent for extraction of fumonisins from naturally contaminated tortilla chips and infant cereals. Study of naturally contaminated corn starch was confounded by instability of fumonisins in this food. Recovery of fumonisins from spiked corn meal, tortilla chips, corn flakes, various types of beans and infant cereals with solvent A and/or solvent B (or BB) was satisfactory.

Approaches to the risk assessment of fumonisins in corn-based foods in Canada.

The presence of fumonisins and associated mycotoxins from Fusarium moniliforme in corn-based foods has recently become a concern in North America and elsewhere. Monitoring of various corn based foods and food commodities for fumonisins is ongoing in both the USA and Canada, and the results can be used for preliminary exposure assessments. The role of Fusarium moniliforme and the fumonisins in some diseases of livestock has been established. Considerable information is available on the mechanism of action of the fumonisins. With the availability of increased quantities of pure fumonisins, several subchronic toxicity studies, designed to establish dose response characteristics in rodents have now been completed. However, since concerns about the chronic toxicity of the fumonisins have not yet been adequately addressed, a tolerable daily intake cannot be established at this time. With the information at hand it is, nevertheless, possible to arrive at an interim risk assessment, which can be used to make interim risk management decisions. A total of 361 samples, covering 4 years of a Canadian survey, have been analyzed to date. Of these, 64 contained > or = 0.1 micrograms/g fumonisin B1, and 10 contained > or = 1 microgram/g. The 'all persons' estimate for the intake of fumonisins from these foods was < 0.089 micrograms/kg bw for 5-11 year-old children, and lower for other age groups. Based on an assessment of the available information on the toxicity of fumonisins, it can be concluded that these estimated intakes are unlikely to pose a health risk.

Application of capillary gas chromatography to a survey of wheat for five trichothecenes.

A previously published method for the determination of deoxynivalenol (DON) and nivalenol (NIV) in grains by capillary gas chromatography (GC) with electron-capture detection (ECD) has been modified to include HT-2 toxin (HT-2), T-2 toxin (T-2) and diacetoxyscirpenol (DAS). Recoveries of the five trichothecenes from wheat averaged 71-92% in the range 0.8-4 micrograms/g. Detection or quantitation limits found in two laboratories were from 0.02 to 0.4 micrograms/g, with those for T-2 and DAS at the high end of this range. The method proved of practical use in survey work for the screening and determination of these trichothecenes in wheat from the 1987 western Canadian crop. There were no false positives for HT-2, T-2 and DON in durum and HY-320 wheat. However, interferences precluded the determination of 4- and 15-monoacetoxyscirpenol (MAS) by GC-ECD. The natural occurrence of HT-2 toxin (0.06-0.59 micrograms/g) was demonstrated by GC-ECD and confirmed by GC-mass spectrometry (MS) in 23 samples of durum and HY-320 wheats (1986 and 1987 crops); it was almost always accompanied by DON and in one sample a low concentration of NIV (0-05 micrograms/g). False positives for HT-2 and DAS in red spring wheat detected in 1987 by GC-ECD were 6% (nearly all identified as variety Katepwa) and 8%, respectively. Hence confirmation of suspected HT-2 and DAS by GC-MS is necessary, particularly with red spring wheat.