Application of a monoclonal-based immunoassay for the determination of imazalil in fruit juices

A monoclonal antibody-based enzyme-linked immunosorbent assay (ELISA) was developed for the quantification of imazalil [(RS)-1-(β-allyloxy-2,4-dichlorophenylethyl)imidazole] in apple, tomato and orange juice samples. From an imazalil hapten, which mimics the analyte structure, several monoclonal antibodies were obtained. An ELISA in the conjugate-coated format was developed and optimized using the antibody showing the highest sensitivity. For standards, the detection limit of the ELISA was 0.2 nM (0.06 ng ml^-1), with an I₅₀ value of 1.6 nM (0.5 ng ml^-1). The study of the influence of matrices on assay reliability indicated that the ELISA could determine imazalil in fruit juices at the low ng ml^-1 level simply by diluting the sample, without any clean-up or concentration step. Recovery and precision of the method were evaluated by spiking juice samples with imazalil in the 10-500 ng ml^-1 range. The mean recovery from fruit juices was 97% and the mean coefficient of variation was ∼20%. In addition to being precise and accurate, the method has proved to be simple and sensitive, with a quantification limit well below the maximum residue limits for imazalil in these matrices.     

Investigation of patulin contamination in apple juice sold in retail outlets in Italy and South Africa

A study of apple juice products sold in Italy and South Africa was initially carried out on 20 samples bought in Cesena, Italy, and Tygerberg in Cape Town, South Africa. The samples were bought at random and analysed for patulin contamination. All 12 of the Italian samples had no detectable levels of patulin, except one, which was just slightly above the lowest regulatory limit of 10 ng ml^-1. On the other hand, five of the eight South African samples were all contaminated with patulin levels above 10 ng ml^-1, with one showing a concentration of 75 ng ml^-1, well above the highest regulated limit of 50 ng ml^-1. This latter result led to a more targeted investigation with 14 samples being purchased in the low-income areas of Tygerberg where the initial samples were sourced. These samples confirmed that there might be a problem of mycotoxin contamination in apple juices products sold to low-income consumers because half of the samples showed patulin contamination of which four had levels well above the acceptable limits. This is the first study in South Africa to look at apple juice products in low-income areas and it points to a need to intervene and introduce quality systems in the supply chain of the manufacture and packaging of apple juice products by independent small business.     

Determination of ochratoxin A in grapes of Greek origin by immunoaffinity and high-performance liquid chromatography

A simple analytical method for ochratoxin A (OTA) determination in grapes is described, using aqueous methanolic extraction, an immunoaffinity column clean-up step and high-performance liquid chromatography with fluorescence detection. Mean recovery was 94% (RSD = 4.0%) with a detection limit of 0.4 ng g^-1 and quantification limit of 1.20 ng g^-1. Repeatability (r) and reproducibility (R) were 1.17 and 1.34, respectively. OTA determinations were applied to 50 grape samples (23 different varieties) originating from representative regions of Greece. Results showed the presence of OTA in 86% of samples tested (n = 50). Traces were found in 56% of samples but OTA was not detectable in 14% of samples. Traces were also found in 4% of red, organically grown samples. The most contaminated were three samples of red grapes, two from Central Greece (2.69 and 1.41 ng g^-1), both table and wine-making grapes. The third sample (1.46 ng g^-1), originating from the island of Samos, was used only in wine-making. Mean (1.06 ng g^-1) and median (0.76 ng g^-1) OTA concentrations in red grapes were slightly higher compared to the mean (0.82 ng g^-1) and median (0.65 ng g^-1) concentrations in white grape samples. The study shows that the potential risk for a person of 60 kg ranged from 0.9 to 9 ng kg^-1 bw day^-1 and is dependent on the quantity of grapes consumed daily.     

Occurrence of aflatoxin M1 in randomly selected North African milk and cheese samples

Forty-nine samples of raw cow's milk and 20 samples of fresh white soft cheese were collected directly from 20 local dairy factories in the north-west of Libya and analysed for the presence of aflatoxin M₁ (AFM₁). The samples were analysed using a high-performance liquid chromatography technique for toxin detection and quantification. Thirty-five of the 49 milk samples (71.4%) showed AFM₁ levels between 0.03 and 3.13 ng ml^-1 milk. Multiple analyses of five milk samples free of AFM₁ artificially contaminated with concentrations of AFM₁ at 0.01, 0.05, 0.1, 1.0 and 3.0 ng ml^-1 showed average recoveries of 66.85, 72.41, 83.29, 97.94 and 98.25%, with coefficients of variations of 3.77, 4.11, 1.57, 1.29 and 0.54%, respectively. Fifteen of 20 white soft cheese samples (75.0%) showed the presence of AFM₁ in concentrations between 0.11 and 0.52 ng g^-1 of cheese. Multiple assays of five cheese samples free of AFM₁ spiked with different concentration of AFM₁ (0.1, 0.5, 1.0 and 3.0 ng g^-1) showed average recoveries of 63.23, 78.14, 83.29 and 88.68%, with coefficients of variation of 1.53, 9.90, 4.87 and 3.79%, respectively. The concentrations of AFM₁ were lower in the cheese products than in the raw milk samples.     

Intake of ochratoxin A and deoxynivalenol through beer consumption in Belgium

Estimations of ochratoxin A (OTA) and 4-deoxynivalenol (DON) exposure of the Belgian population through beer consumption were made using the results of the recent Belgian food survey and the compiled data set of OTA and DON levels in conventionally and organically produced beers in 2003-05. For the consumers of organic beers, the daily intake of OTA was 0.86 (in 2003), 1.76 (in 2004) and 0.72 (in 2005) ng kg^-1 body weight (bw), considering the mean beer consumption (0.638 litres) and the average level of OTA in 2003, 2004 and 2005, respectively. Using the 97.5th percentile of beer consumption (1.972 litres), the corresponding OTA daily intakes were 2.65, 5.44 and 2.24 ng kg^-1 bw, which are close or above the tolerable daily intake (TDI) of 5 ng kg^-1 bw. For the consumers of conventional beers, the OTA intakes were low: 0.23, 0.23 and 0.11 ng kg^-1 bw day^-1 for the average beer consumption, in 2003, 2004 and 2005 against 0.72, 0.73 and 0.34 ng kg^-1 bw day^-1 when the 97.5th percentile level was considered. As for the DON intake, the estimates were quite low for both conventional and organic beer consumers when the provisional maximum TDI (PMTDI) of 1 µg kg^-1 bw was considered. Average consumption of organic beer led to daily intakes of 0.05 and 0.04 µg DON kg^-1 bw in 2003 and 2004, respectively, whilst for conventional beer, daily intakes were 0.07 and 0.05 µg DON kg^-1 bw. At the 97.5th percentile level of beer consumption, daily intakes of 0.15 and 0.13 µg kg^-1 bw were obtained for organic beers against 0.23 and 0.17 µg kg^-1 bw for conventional ones. The results showed that beer could be an important contributor to OTA exposure in Belgium, even though a declining trend seems to be apparent during the last year of monitoring. Therefore, efforts should be devoted to maintain the OTA levels as low as reasonably achievable, especially for organic beer.     

Effects of Fusarium toxin-contaminated wheat and feed intake level on the biotransformation and carry-over of deoxynivalenol in dairy cows

An experiment was carried out to examine the effects of feeding Fusarium toxin-contaminated wheat (8.21 mg deoxynivalenol (DON) and 0.09 mg zearalenone (ZON) per kg dry matter) at different feed intake levels on the biotransformation and carry-over of DON in dairy cows. For this purpose, 14 ruminal and duodenal fistulated dairy cows were fed a diet containing 60% concentrate with a wheat portion of 55% (Fusarium toxin-contaminated wheat (mycotoxin period) or control wheat (control period)) and the ration was completed with maize- and grass silage (50 : 50) on a dry matter basis. Daily DON intakes ranged from 16.6 to 75.6 mg in the mycotoxin period at dry matter intakes of 5.6-20.5 kg. DON was almost completely biotransformed to de-epoxy DON (94-99%) independent of the DON/feed intake, and the flow of DON and de-epoxy DON at the duodenum related to DON intake ranged from 12 to 77% when the Fusarium toxin-contaminated wheat was fed. In the serum samples, de-epoxy DON was detected in the range of 4-28 ng ml^-1 in the mycotoxin period, while concentrations of DON were all below the detection limit. The daily excretion of DON and de-epoxy DON in the milk of cows fed the contaminated wheat varied between 1 and 10 µg and between 14 and 104 µg, respectively. The total carry-over rates as the ratio between the daily excretion of DON and de-epoxy DON into milk and DON intake were in the ranges of 0.0001-0.0002 and 0.0004-0.0024, respectively. Total carry-over rates of DON as DON and de-epoxy DON into the milk increased significantly with increasing milk yield. In the urine samples, de-epoxy DON was the predominant substance as compared with DON with a portion of the total DON plus de-epoxy DON concentration to 96% when the Fusarium toxin-contaminated wheat was fed, whereas the total residues of DON plus de-epoxy DON in faeces ranged between 2 and 18% of DON intake in the mycotoxin period. The degree of glucuronidation of de-epoxy DON was found to be approximately 100% in serum. From 33 to 80% of DON and from 73 to 92% of de-epoxy DON, and from 21 to 92% of DON and from 86 to 100% of de-epoxy DON were glucuronidated in the milk and urine, respectively. It is concluded that DON is very rapidly biotransformed to de-epoxy DON in the rumen and only negligible amounts of DON and de-epoxy DON were transmitted into the milk within the range of 5.6-20.5 kg day^-1 dry matter intake and milk yields (fat corrected milk) between 10 and 42 kg day^-1.     

Development of a lateral flow immunoassay strip for screening of sulfamonomethoxine residues

A rapid lateral flow immunoassay screening method has been developed for the determination of sulfamonomethoxine (SMM) residues in swine urine. For this purpose, a specific monoclonal antibody (mAb), SMM4B9 for SMM, was generated and characterized. The mAb showed low cross-reactivity (not larger than 0.3%) to other sulfonamides and other potentially occurring analytes. Based on the competitive immunoassay principle, the strip was developed with the mAb SMM4B9 and applied to the screening of SMM residues. The test strip is made up of a sample pad, a gold-conjugate SMM4B9 reagent pad, a blotted test membrane containing a test line, a control line (a nitrocellulose membrane spotted with SMM-BSA and goat anti-mouse antibody, respectively), and an absorbent pad. The test could be accomplished within 8-10 min. It was shown that the sensitivity of the test strip was as low as 5 ng ml^-1 of SMM and the half of maximal inhibition concentration (IC₅₀) was calculated to be 10.78 ± 0.22 ng ml^-1 by relative optical density. In unaided visual assessment the detection limit of the strip was 15 ng ml^-1. For samples spiked at 20 and 30 ng ml^-1 the coefficient of variation (CV (%)) was between 2.3 and 7.1%. When the test strip was compared with high-performance liquid chromatography (HPLC) analysis for naturally contaminated swine urine samples, the difference in results was less than 6.1%. The data suggest that the method has advantages of high sensitivity, specificity, simplicity and speed of performance, as well as the characteristics of repeatability, reproducibility or accuracy and assurance. Therefore, the test strip is suitable to determine SMM residues in swine urine rapidly and reliably by quantitative, semi-quantitative or qualitative detection.     

Occurrence of ivermectin in bovine milk from the Brazilian retail market

High-performance liquid chromatography (HPLC) with fluorescence detection was used for the quantification of ivermectin residues in bovine milk intended for human consumption. After liquid-liquid extraction of ivermectin and purification of the extract, the compound was derivatized with 1-methylimidazol in N,N-dimethyl formamide to form a fluorescent derivative, which was separated by HPLC, using reversed-phase C₁₈, with methanol : water (96 : 4 v/v) mobile phase at a flow rate 0.7 ml min^-1. The excitation and emission wavelengths of the fluorescence detector were adjusted at 360 and 470 nm, respectively. The linearity of the method was in the range 10-100 ng ivermectin ml^-1. Based on a sample of 5.0 ml, the limit of detection and the limit of quantification for ivermectin in milk were 0.6 and 2 ng ml^-1, respectively. The recovery rate varied from 76.4 to 87.2%, with an average of 77.9 ± 3.2%, at four fortification levels. The inter-day precision of the method was 13% (n = 5). Of 168 samples analysed, 17.8% contained ivermectin above the limit of quantification. Nevertheless, none of the samples contained ivermectin above the maximum residue limit (10 ng ml^-1) established by the Brazilian Ministry of Agriculture.     

Survey of aflatoxins in beer sold in Canada

Between March 1998 and March 2002, 304 samples of domestic (Canadian) and imported beers from 36 countries were picked up for the determination of aflatoxins B₁, B₂, G₁ and G₂. Twelve samples were positive with aflatoxins greater than the limit of quantitation (LOQ) (aflatoxin B₁, 4.4 ng l^-1; aflatoxin B₂, 3.4 ng l^-1; aflatoxin G₁, 11.2 ng l^-1; and aflatoxin G₂, 6.2 ng l^-1). Five samples from Mexico, two samples from Spain and one from Portugal contained aflatoxin B₁. Four samples from India contained aflatoxins B₁ and B₂. The remaining samples contained less than the LOQ for aflatoxins B₁, B₂, G₁ and G₂. The analytical method for this survey was based on that of Scott and Lawrence (Scott PM, Lawrence GA. 1997. Determination of aflatoxins in beer. Journal of AOAC International 80:1229-1234.). Aflatoxins B₁, B₂, G₁ and G₂ were determined at parts per trillion (ng l^-1) levels in beer by immunoaffinity column cleanup followed by derivatization with trifluoroacetic acid and reversed-phase liquid chromatography with fluorescence detection.     

Determination of ochratoxin A in virgin olive oils of Greek origin by immunoaffinity column clean-up and high-performance liquid chromatography

An improved specific analytical method for ochratoxin A (OTA) determination in olive oil is described, using a methanolic-aqueous extraction, an immunoaffinity column clean up step and high-pressure liquid chromatography with fluorescence detection. The mean recovery was found at 108% (relative standard deviation, RSD = 4.7%) and the detection limit (DL) was estimated at 4.6 ng kg^-1. Along with OTA, aflatoxin B₁ (AFB₁) was determined using the same extract. The recovery factor was 84.8% (RSD = 17.8%) and the DL was 56 ng kg^-1 olive oil. Both determinations were applied in 50 samples of olive oil originated from representative regions of Greece. Results revealed the presence of OTA in 88% of samples tested (n = 44, mean 267 ng kg^-1). Among them, 10 were contaminated with more than 500 ng kg^-1 (median 568 ng kg^-1), 10 with 200-500 ng kg^-1 (median 260 ng kg^-1), 15 with 100-200 ng kg^-1 (median 140 ng kg^-1), nine with DL-100 (median 60 ng kg^-1) and in six samples, OTA was not detectable. Interestingly, most contaminated samples were from Southern Greece. Results of AFB₁ determination showed the presence of aflatoxin B₁ (60 ng kg^-1) in only one olive oil sample also from Southern Greece. The levels of OTA found in Greek olive oil were relatively low as compared with other commodities such as cereals or wine reported in the literature.     

Analysis of veterinary drug residues in fish and shrimp composites collected during the Canadian Total Diet Study, 1993-2004

Thirty shrimp, marine fish, freshwater fish, and canned fish composite samples collected and prepared as part of the Canadian Total Diet Study were analysed for 39 different veterinary drug residues. The analyses were undertaken to obtain baseline data that could be used to estimate the dietary exposure of Canadians to these residues. The most frequently observed residue was AOZ (four out of 30 samples), the metabolite of furazolidone, at a range of 0.50 to 2.0 ng g^-1 wet weight. Other residues detected included enrofloxacin (three samples; 0.3-0.73 ng g^-1), leucomalachite green (three samples; 0.73-1.2 ng g^-1), oxolinic acid (two samples; 0.3-4.3 ng g^-1), AMOZ (the metabolite of furaltadone; one sample; 0.40 ng g^-1), chloramphenicol (one sample; 0.40 ng g^-1), and SEM (the metabolite of nitrofurazone; one sample; 0.8 ng g^-1). The results of this survey indicate that Canadians are exposed to low ng g^-1 concentrations of some banned and unapproved veterinary drug residues via the consumption of certain fish and shrimp.     

Determination of carbendazim residues in fruit juices by liquid chromatography-tandem mass spectrometry

In this paper a rapid optimized method for routine analysis of carbendazim residues in fruit juices is reported. The procedure is based on matrix solid-phase dispersion (MSPD) with diatomaceous earth and analysis of the extract by liquid chromatography-tandem mass spectrometry, with electrospray ionization (LC-ESI-MS/MS). In the method optimization, finding of the optimal pH for the extraction of carbendazim from juice was particularly critical. Significant matrix effects were observed, but could be eliminated using matrix-matched standards. High recoveries (82-102%), good repeatability (RSD ≤ 12%) and low limits of detection (0.03 ng ml^-1) and quantification (0.1 ng ml^-1) were achieved with this method.     

Analysis of heat-processed corn foods for fumonisins and bound fumonisins

Thirty retail samples of heat-processed corn foods, i.e. corn flakes, corn-based breakfast cereals, tortilla chips and corn chips, were analysed for fumonisins — fumonisin B₁ (FB₁), fumonisin B₂ (FB₂) and hydrolysed FB₁ (HFB₁) — as well as for protein- and total-bound FB₁. Bound (hidden) fumonisins cannot be detected by conventional analysis. Improved methods for the determination of bound FB₁ were developed. The protein-bound FB₁ was extracted with 1% sodium dodecylsulfate (SDS) solution. The SDS, which interfered with high-performance liquid chromatography (HPLC) analysis, was then separated from protein-bound FB₁ by complexing with methylene blue followed by solvent extraction and hydrolysis with 2 N KOH. To measure total-bound FB₁, the sample itself was hydrolysed with KOH. In both cases, clean-up was accomplished on an OASIS polymeric solid-phase extraction column and the bound fumonisins were determined by HPLC measurement of HFB₁. Fourteen of 15 samples of corn flakes and other corn-based breakfast cereals analysed contained detectable levels of FB₁ with a mean in positive samples of 67 ng g^-1 (13-237 ng g^-1). Two samples also had detectable levels of FB₂ (21-23 ng g^-1). Bound FB₁ was found in all samples; the mean protein-bound FB₁ measured was 58 ng g^-1 (22-176 ng g^-1) and the mean total-bound FB₁ measured was 106 ng g^-1 (28-418 ng g^-1), reported as FB₁ equivalents after correction for recoveries of HFB₁. There was an average of about 1.3 times more FB₁ in the bound form compared with extractable FB₁, and this was about twice as much as protein-bound FB_1. Seven of the 15 samples of alkali-processed corn-based foods, such as tortilla chips and corn chips, contained FB₁ and three contained HFB₁ with means in measurable positive samples of 78 (48-134) and 29 (13-47) ng g^-1, respectively. Five of these alkali-processed corn foods contained bound FB₁; the mean measurable protein-bound FB₁ was 42 ng g^-1 (39-46 ng g^-1) and the mean measurable total-bound FB₁ was 100 ng g^-1(54-209 ng g^-1). HFB₁ derived from bound FB₁ in selected samples was confirmed by HPLC with mass spectrometry (MS).     

Occurrence of fumonisins B1 and B2 in asparagus from Shandong province, P.R. China

Thirty samples of asparagus spears were collected from the fields in Shandong province, China, in July 2004, and were analysed for the occurrence of fumonisins B₁ and B₂ (FB₁ and FB₂) by HPLC coupled with electrospray ionization tandem mass spectrometry. Twenty-four samples (80%) contained fumonisins, ranging from 24 to 670 ng g^-1 (average 123 ng g^-1) and 17 to 138 ng g^-1(average 35 ng g^-1) for FB₁ and FB₂, respectively. The total amount of fumonisins (FB₁ and FB₂) in all samples ranged from 47 to 714 ng g^-1 (average 158 ng g^-1) (based on dry weight). This is the first report on the natural occurrence of FB₁ and FB₂ in asparagus spears in China.     

N-methyl carbamate pesticide residues in conventional and organic infant foods available on the Canadian retail market, 2001-03

Seven parent N-methyl carbamate insecticides, in addition to two transformation products of aldicarb (aldicarb sulfoxide and aldicarb sulfone), and a single transformation product of carbofuran (3-hydroxycarbofuran) were measured in infant and junior foods available on the Canadian retail market between 2001 and 2003. Carbaryl and methomyl were the only analytes present at levels above the limits of detection in juice, cereals, fruit, vegetables or meat samples analysed. Carbaryl was the most frequently (7.6%) detected compound and concentrations ranged from 0.6 to 18 ng g^-1. Detectable levels of carbaryl were most frequently found in foods prepared with fruit. Methomyl was detected (0.8 ng g^-1) in one chicken with broth sample analysed in the present study. In all cases, the concentrations observed were orders of magnitude below the maximum residue limits established for these compounds in the corresponding raw food commodities in Canada (100-10 000 ng g^-1). Dietary intakes of carbaryl and methomyl based on the consumption of infant foods tested ranged between 0.2-343 and 0.4-2.0 ng kg^-1 body weight day^-1, respectively.     

Detection of dehydroepiandrosterone and androsterone in a traditional Chinese herbal product

Dehydroepiandrosterone (DHEA) and androsterone (ADT) were detected in a traditional Chinese herbal product by gas chromatography-mass spectrometry (GC-MS) and liquid chromatography tandem mass spectrometry (LC-MS/MS). DHEA and ADT were tentatively identified by comparing their electron ionization (EI) mass spectra with those in the GC-MS Wiley database. A multiple reaction monitoring (MRM) scan was performed in LC-MS/MS to confirm the presence of the DHEA and ADT in the herbal product extract. Both the [M + H]⁺ and the [M + NH₄]⁺ of DHEA and ADT were selected as the precursor ions. DHEA was detected with ion transitions m/z 306.4 → 271.2, 306.4 → 253.3, 289.2 → 270.9, 289.3 → 253.1 while ADT was detected with ion transitions m/z 308.5 → 273.6, 308.5 → 255.3, 291.5 → 273.5, 291.5 → 255.2, which confirmed the presence of the two steroid hormones in the herbal product. Limits of detection (LODs) of 0.2 µg ml^-1 for DHEA and 0.3 µg ml^-1 for ADT were found in methanolic standard solutions when [M + NH₄]⁺ of DHEA and ADT were selected as the precursor ions, which allowed the detection of DHEA and ADT at trace level without time-consuming derivatization.     

Deoxynivalenol and other Fusarium toxins in wheat and rye flours on the Danish market

Information on the contamination of Danish cereals and cereal products with Fusarium toxins is limited and the last survey is from 1984/1985. In the present study, the occurrence of deoxynivalenol (DON), nivalenol (NIV), HT-2 toxin, T-2 toxin and zearalenone (ZON) was investigated in flour of common wheat, durum wheat and rye. The samples were collected from 1998 to 2001 from both mills and the retail market in Denmark. A total of 190 flour samples were analysed for DON and NIV and about 60 samples for HT-2, T-2 toxin and ZON. DON was most frequently detected with an incidence rate of 78% over all samples for all years. The contamination level varied considerably from year to year, and for wheat and rye the highest incidence and DON concentrations were found in samples from the 1998 harvest. There were regular and heavy rainfalls in Denmark during the flowering period of the crops that year, and DON was found in all samples, with mean concentrations in wheat and rye flour of 191 μg kg^-1 (n =14) and 99 μg kg^-1 (n =16), respectively. Comparison of data from each harvest year showed higher contents of DON in samples of wheat (range 20-527 μg kg^-1) than in rye (20-257 μg kg^-1). Contents of NIV, HT-2 toxin and ZON in samples of wheat and rye were generally low, and even in positive samples the contents were close to the detection limit of the methods. The T-2 toxin was detected in only a few of the wheat samples and in low amounts. However, the toxin was found in about 50% of the rye samples collected during 1998-2000, with a mean content of 49 μg kg^-1 (n =25). Durum wheat flour showed the highest DON contamination level, and all samples (n =33) collected during 2000 and 2001 contained DON with means and medians above 1100 μg kg^-1. Over 70% of the samples contained more than 500 μg kg^-1 DON, and the highest observed concentration was 2591 μg kg^-1. The concentration of T-2 toxin in durum wheat flour was also high with five of the 10 analysed samples containing more than 100 g kg^-1.     

A sensitive solid-phase microextraction/gas chromatography-based procedure for determining pentachlorophenol in food

A new method for the determination of pentachlorophenol (PCP) in different foods was developed using capillary gas chromatography (GC) and microwave induced-plasma atomic emission spectrometry (MIP-AED). The analyte is first derivatized and then extracted and pre-concentrated by solid-phase microextraction (SPME) in headspace (HS) mode. A clear matrix effect was found for the different samples investigated, so that standard addition was required for quantification. Detection limits of 0.03-6.0 ng g^-1 were obtained, depending on the sample analysed. The method gave recoveries of 81-109% from spiked samples. Concentration levels of PCP ranged from 0.3 to 1.5 ng g^-1 were found in honey, but no PCP was detected in other samples.     

Distribution and elimination of fumonisin analogues in weaned piglets after oral administration of Fusarium verticillioides fungal culture

The distribution and elimination of fumonisins after oral administration of 50 mg FB₁, 20 mg FB₂ and 5 mg FB₃ per animal day^-1 for 22 days was studied in weaned barrows. At the end of the trial, the lung, heart, liver, kidney, spleen, brain, serum, bile, muscle, fat, urine and faeces samples were collected and their content of fumonisins (FB₁, FB₂) determined by LC-MS. The highest FB₁ concentrations were found in the liver (99.4 ± 37.5 ng g^-1) and kidneys (30.6 ± 10.1 ng g^-1), whilst the highest average amount of FB₂ was in the liver (1.4 ± 2.3 ng g^-1) and fat (2.6 ng g^-1 ± 4.8) samples. Comparing the FB₁/FB₂ ratio in different organs (19/1), it was found that the ratio in the abdominal and subcutaneous fat samples (4/1) was markedly different from those in all other tissues, namely the relative proportion of FB₂ was higher in latter cases. Of the total quantity of FB₁, the 13% taken up during 5 days was excreted unchanged with the faeces and urine. On average, in the urine and faeces, FB₁ was detected in nine- and 14-fold quantities, as compared with FB₂.     

Clostridium perfringens and its toxins in minced meat from Kars, Turkey

The aim of this study was to determine the prevalence of Clostridium perfringens and its toxins in minced meat. A total of 96 minced meat samples were collected from local markets (16) and small butcher's shops (80) in Kars (Turkey). Samples were analysed for the presence of C. perfringens and its toxins using a commercially available ELISA kit. A total of 31 (32%) Clostridium spp. strains were isolated and 17 (55%) of these isolates were identified as C. perfringens. Four (25%) of the samples from local markets and 27 (34%) from small butcher's shops were contaminated with Clostridium spp. Furthermore, C. perfringens was isolated from two (12%) and 15 (19%) samples from local markets and small butcher's shops, respectively. Mean counts of Clostridium spp. were 2.2 ± 0.83 × 10² CFU g^-1 for local markets and 4.35 ± 8.53 × 10² CFU g^-1 for small butcher's shops; mean counts for C. porringers were 2.75 ± 0.21 × 10² and 6.82 ± 10.96 × 10² CFU g^-1 from markets and butcher's shops, respectively. The number of samples contaminated with both Clostridium spp. and C. perfringens was higher in small butcher's shops than in local markets. Moreover, higher numbers of Clostridium spp. and C. perfringens were isolated in samples from small butcher's shops than from local markets. A total of 13 (13%) samples were also positive for toxins produced by the organism, as detected by ELISA. Eleven samples from small butcher's shops and two samples from local markets were positive for the C. perfringens toxins tested. Moreover, two (12%), one (1%), four (4%) and two (2%) samples were contaminated with C. perfringens types A, B, C and D, respectively. In conclusion, some meat samples collected from local markets and small butcher's shops contained C. perfringens and its toxins and, therefore, present a potential risk of food poisoning.