Occurrence of aflatoxin M1 in commercial pasteurized milk determined with ELISA and HPLC

Compliance between Food and Feed Safety: Eight-Year Survey (2013–2021) of Aflatoxin M1 in Raw Milk and Aflatoxin B1 in Feed in Northern Italy

Aflatoxins (AFs) are fungal metabolites that are found in feed and food. When ruminants eat feed contaminated with aflatoxin B1 (AFB1), it is metabolised and aflatoxin M1 (AFM1) is excreted in the milk. Aflatoxins can result in hepatotoxic, carcinogenic, and immunosuppressive effects. The European Union thus set a low threshold limit (50 ng/L) for presence of AFM1 in milk. This was in view of its possible presence also in dairy products and that quantification of these toxins is mandatory for milk suppliers. In the present study, a total of 95,882 samples of whole raw milk, collected in northern Italy between 2013 and 2021, were evaluated for presence of AFM1 using an ELISA (enzyme-linked immunosorbent assay) method. The study also evaluated the relationship between feed materials collected from the same farms in the same area during the same period (2013–2021) and milk contamination. Only 667 milk samples out of 95,882 samples analysed (0.7%) showed AFM1 values higher than the EU threshold limit of 50 ng/L. A total of 390 samples (0.4%) showed values between 40 and 50 ng/L, thus requiring corrective action despite not surpassing the regulatory threshold. Combining feed contamination and milk contamination data, some feedingstuffs seem to be more effective in defying potential carryover of AFs from feed to milk. Combining the results, it can be concluded that a robust monitoring system that covers both feed, with a special focus on high risk/sentinel matrices, and milk is essential to guarantee high quality and safety standards of dairy products.

Aflatoxin M1 detection by ELISA in raw and processed milk in Bangladesh

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Immunologically aflatoxin M1 was detected in raw and processed milk in Bangladesh.

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Aflatoxin M1 mean level was found to be highest in raw milk (699.07 ng/kg).

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EC and US regulations exceeded in 75 % and 43 % of contaminated samples, respectively.

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Aflatoxin M1 existence level in milk can be detrimental to human health.

An analysis was accomplished to get information regarding presence of highly toxic and carcinogenic aflatoxin M1 (AFM1) in raw and processed samples of milk applying ELISA (enzyme linked immunosorbent assay). Investigation of a set of 100 samples (n=100) taken from different regional small-scale farms as well as grocery stores of Bangladesh containing three groups of milk including raw (n=50), pasteurized (n=25) and UHT (n=25), exhibited in total 53% AFM1 contamination where 70% contamination was found in raw milk ranging from 22.79−1489.28 ng/kg (mean value 699.07 ng/kg), 52% in pasteurized milk ranging from 18.11−672.18 ng/kg (mean value 99.77 ng/kg) and 20% in UHT milk ranging from 25.07−48.95 ng/kg (mean value 35.46 ng/kg). Among all the positive samples, 75% contaminated samples were above the European Communities prescribed limits (50 ng/kg) while having 25% samples still below this limit whereas 43% samples crossed the accepted limit of US regulations/Codex Alimentarius Commission regulations (500 ng/kg). Thus the findings of this study may lead to increase awareness regarding health impact of aflatoxin M1 and implementation of strict regulations by law enforcement bureaus of Bangladesh.

Aflatoxin M1 contamination level in Iranian milk and dairy products: a systematic review and meta-analysis

Aflatoxin M1 is a derivate of aflatoxin B1 and an important contaminant of milk and dairy products. This systematic review and meta-analysis was conducted on relevant Persian and English original articles in national and international databases with no time limits until 1 January 2018. In total 605 articles were found among which 70 articles met the inclusion criteria for meta-analysis. The prevalence (95% confidence interval (CI)) and mean concentration (95% CI) of aflatoxin M1 was found to be 64% (53-75%) and 39.7 ng/l (31.9-47.4 ng/l) in raw milk, 95% (89-98%) and 62.3 ng/l (40.6-84 ng/l) in pasteurised milk, 71% (56-84%) and 60.1 ng/l (30.9-89.3 ng/l) in sterilised milk, 59% (20-93%) and 5.5 ng/l (3.3-7.7 ng/l) in breast milk and 72% (61-81%) and 82.3 ng/kg (63.7-100.9 ng/kg) in dairy products. In general, 9% (4-16%) of milks and 10% (4-17%) of dairy products had aflatoxin M1 in concentrations exceeding the permitted level of Iranian standards (500 ng/l). Based on the maximum permitted aflatoxin M1 concentration in standards of Europe (50 ng/l), these percentages increase to 25% (18-32%) for milks and 18% (9-29%) for dairy products. According to the results, further control and preventive measures should be applied on livestock feeds because decreased aflatoxin B1 contamination at this level results in decreased aflatoxin M1 in milk and dairy products.

Aflatoxin M1 in milk in Hisar city, Haryana, India and risk assessment

Aflatoxin M1 (AFM1) contamination in 150 samples of milk, sold in market of Hisar city of Haryana, India, was investigated by using High Pressure Liquid Chromatography (HPLC). Out of these, 40 samples contained AFM1 at a concentration below the limit of detection (LOD) of 0.052 μg/kg. Among the AFM1 contaminated samples, 46 raw milk samples contained a concentration above the LOD but less than the limit of quantitation (LOQ), whereas 64 samples were above the LOQ. Of these samples, 31 exceeded the maximum limit of 0.5 μg/kg prescribed by FSSAI, India. Based on this study, the dietary intake of AFM1 for adults through consumption of milk was estimated. The results indicated that AFM1 contamination can be a food safety issue for raw and pasteurised milk consumed in India. Therefore, there is a need for a national monitoring programme to control the level of mycotoxins in milk.

AFM1 Detection in Milk by Fab' Functionalized Si3N4 Asymmetric Mach-Zehnder Interferometric Biosensors

Aflatoxins (AF) are naturally occurring mycotoxins, produced by many species of Aspergillus. Among aflatoxins, Aflatoxin M1 (AFM1) is one of the most frequent and dangerous for human health. The acceptable maximum level of AFM1 in milk according to EU regulation is 50 ppt, equivalent to 152 pM, and 25 ppt, equivalent to 76 pM, for adults and infants, respectively. Here, we study a photonic biosensor based on Si 3 N 4 asymmetric Mach-Zehnder Interferometers (aMZI) functionalized with Fab' for AFM1 detection in milk samples (eluates). The minimum concentration of AFM1 detected by our aMZI sensors is 48 pM (16.8 pg/mL) in purified and concentrated milk samples. Moreover, the real-time detection of the ligand-analyte binding enables the study of the kinetics of the reaction. We measured the kinetic rate constants of the Fab'-AFM1 interaction.

Occurrence and seasonality of aflatoxin M1 in milk in two different climate zones

BACKGROUND

Aflatoxin M1 (AFM1) is a mycotoxin found in milk as a result of the ingestion of aflatoxin B1 (AFB1) by dairy cattle. Because of its carcinogenic properties, the control of its occurrence in dairy products is of great importance. We evaluated the occurrence and seasonality of AFM1 in milk from farms with subtropical and temperate climates, where significant milk production occurs. Forty samples of raw milk were collected from bulk tansk milk during the summer (five samples from a subtropical climate and 14 from a temperate climate) and winter (six samples from a subtropical climate and 15 from a temperate climate) months of 2017 and conducted an analysis using an enzyme-linked immunosorbent assay (ELISA) (detection limit 5 ng L^-1 ). Data from eight random samples were compared with respect to liquid chromatography with mass spectrometry detection and ELISA. A significant correlation was observed.

RESULTS

The presence of AFM1 was detected in 87.50% (n = 35) of the samples analyzed (a mean of 16.66 ng L^-1 and a median of 12.42 ng L^-1 in positive samples); however, its concentration in all samples was below the maximum limit allowed by European (50 ng L^-1 ) and Brazilian (500 ng L^-1 ) legislations. There were no significant differences in the levels of AFM1 between the properties located in the two climate zones, in both summer and winter. The estimated daily intake of AFM1 based on the milk analyzed was 0.0107 ng kg^-1 day^-1 for adolescents, 0.0072 ng kg^-1 day^-1 for adults and 0.0098 ng kg^-1 day^-1 for the elderly.

CONCLUSION

The present work demonstrated a low exposure to AFM1. © 2018 Society of Chemical Industry.

Optical Biosensors Based on Silicon-On-Insulator Ring Resonators: A Review

Recent developments in optical biosensors based on integrated photonic devices are reviewed with a special emphasis on silicon-on-insulator ring resonators. The review is mainly devoted to the following aspects: (1) Principles of sensing mechanism, (2) sensor design, (3) biofunctionalization procedures for specific molecule detection and (4) system integration and measurement set-ups. The inherent challenges of implementing photonics-based biosensors to meet specific requirements of applications in medicine, food analysis, and environmental monitoring are discussed.

A survey of AFM1 contamination in row cow milk produced in region of Kumanovo

Aflatoxins (AFs) are type of mycotoxins produced by certain Aspergillus species. In the livers of cows, the aflatoxin В1 (AFB1) ingested with contaminated food is metabolized in carcinogenic aflatoxin М1 (AFM1) which is then excreted in the milk and poses a serious risk to the health of the consumers. In January of 2019, twenty five (25) samples of milk were collected from local farms in the surrounding area of Kumanovo, Republic of North Macedonia. The samples were analysed in the Centre for Public Health, Kumanovo. A method MKC EN ISO 14501:2007 for analysis of AFM1 by HPLC with fluorescence detection was applied. This method is selective, precise and applicative. The final analytical result has shown AFM1 below the LOD in any of the analyzed samples. Due to the well-known fact that AFM1 is toxic, i.e. carcinogenic and the fact that milk is widely used as staple food, continuous development as well as introduction of new, more sensitive methods for detection of AFM1 are required. Keywords: Aflatoxin M1, HPLC-FLD, milk

Aptasensors Based on Whispering Gallery Mode Resonators

In this paper, we review the literature on optical evanescent field sensing in resonant cavities where aptamers are used as biochemical receptors. The combined advantages of highly sensitive whispering gallery mode resonator (WGMR)-based transducers, and of the unique properties of aptamers make this approach extremely interesting in the medical field, where there is a particularly high need for devices able to provide real time diagnosis for cancer, infectious diseases, or strokes. However, despite the superior performances of aptamers compared to antibodies and WGMR to other evanescent sensors, there is not much literature combining both types of receptors and transducers. Up to now, the WGMR that have been used are silica microspheres and silicon oxynitride (SiON) ring resonators.

Survey of aflatoxin M₁ in cows' milk from free-grazing cows in Abeokuta, Nigeria

Aflatoxin M1 (AFM1) in milk from 100 different herds of free-grazing cows in Abeokuta, Nigeria, was analysed by immunoaffinity column cleanup and HPLC with fluorescence detection. AFM1 was found in 75% of the samples, the toxin levels in positive samples ranged from 9.0 to 456.0 ng/l. The mean AFM1 level in positive samples was 108.15 ng/l, exceeding, for example, the European Union maximum level by a factor of two. These results indicated that there is an urgent need to more closely control the milk of free-grazing cows for AFM1 in order to protect the health of humans consuming milk and milk products.

Isolation of alpaca anti-idiotypic heavy-chain single-domain antibody for the aflatoxin immunoassay

Anti-idiotypic antibodies recognize the antigenic determinants of an antibody, thus they can be used as surrogate antigens. Single-domain antibodies from camlid heavy-chain antibodies with the benefit features of small size, thermostability, and ease in expression, are leading candidates to produce anti-idiotypic antibodies. In this work, we constructed an antibody phage library from the mRNA of an alpaca immunized with an antiaflatoxin monoclonal antibody (mAb) 1C11. Three anti-idiotypic VHH antibodies were isolated and applied to immunoassay toward aflatoxin as a coating antigen. The best immunoassay developed with one of these VHH antibodies shows an IC50 of 0.16 ng/mL toward aflatoxin B1 and cross-reactivity toward aflatoxin B2, G1, and G2 of 90.4%, 54.4%, and 37.7%, respectively. The VHH-based immunoassay was successfully applied to the analysis of peanuts, corn, and rice, which are the predominant commodities regularly contaminated by aflatoxins. A good correlation (r(2) = 0.89) was found between the data obtained from the conventional ELISA and the ELISA based on a VHH coating antigen for the analysis of aflatoxins in peanuts and feedstuff. The use of biotechnology in developing the surrogate, the absence of standard aflatoxin and organic solvents in the synthesis procedures, and the reproducibility of the VHH antibody makes it an ideal strategy for replacing conventional synthesized antigens.

Cultured mammary epithelial monolayers (BME-UV) express functional organic anion and cation transporters

There is ongoing concern about the potential adverse effects of xenobiotic residues in cows' milk to the human consumer. Although drugs that are intentionally administered to lactating dairy cattle are rigorously regulated to prevent harmful residues, there are numerous other potential sources of exposure that are not as easily controlled. For example, cattle may be exposed to mycotoxins, pesticides and/or persistent organic pollutants through feed, water and inhalation of polluted air. Accurate estimates of the rate and extent of excretion of these compounds into milk is important to assess the risk of exposure through cows' milk. In the present study, the expression of carrier mediated transport processes in cultured monolayers of an immortalized bovine mammary epithelial cell line (BME-UV) was determined using a flow-through diffusion cell system, selective substrates and inhibitors of organic cation transporters (OCT) and organic anion transporters (OAT). The basal-to-apical (BL-to-Ap) flux of tetraethylammonium and estrone sulfate significantly exceeded their flux in the opposite direction. The addition of selective inhibitors to the donor compartment significantly decreased the BL-to-Ap flux of either selective substrate. These results suggest that both OCT and OAT are functionally expressed by BME-UV cells.

Detection of aflatoxin M1 concentrations in UHT milk consumed in Turkey markets by ELISA

In this study, ELISA (Enzyme Linked Immunosorbent Assay) technique was used for detection of aflatoxin M1 in UHT milk sold in Bursa-TURKEY for consumption. A total of 50 samples of commercial UHT (Ultra High Temperature) whole milk were analyzed. Aflatoxin M1 residues were detected in all samples (100%) studied in different levels. The mean value was 101.2 +/- 53.8 ng L(-1). Although, 40 (80%) were below the limit, the remaining 10 (20%) were well above the limit permitted by European Community and Turkish Food Codex. Serious risks for public health exist from milk consumption. Therefore, milk has to be controlled periodically for AFM1 contamination. Also, dairy cow feeds should be stored in such a way that they do not become contaminated.

Detection of aflatoxin M1 in raw and commercial pasteurized milk in Urmia, Iran

During the years 2005 and 2006, samples of raw and of pasteurized milk (72 samples each) were collected randomly from various parts of Urmia city in Iran for the detection of aflatoxin M1. Aflatoxin M1 levels were assessed by Enzyme Linked Immuno Sorbent Assay (ELISA). There was a high incidence of AFM1 (100%), in both raw and pasteurized milk samples. The AFM1 levels in 6.25% of samples were higher than the maximum tolerance limit accepted by European Union (50 ng L(-1)), while the observed mean ofAFM1 was lower than those proposed for European diets. Maximum level ofAFM1 in raw and pasteurized samples were 91.8 and 28.5 ng L(-1), while minimum levels were 4.3 and 5.1 ng L(-1), respectively. The levels ofAFM1 in total samples indicated that feeds for cows in this region were contaminated with AFB1 in such a level that appears to be a serious public health problem at the moment. Therefore, there is a need to limit exposure to aflatoxins by imposing regulatory limits.

Occurrence of aflatoxin M1 in UHT milk in Turkey

Aflatoxin M1 (AFM1) appears in milk as a direct result of the ingestion of food contaminated with aflatoxin B1 by cattle. The role of milk in human nutrition is well-known. The purpose of the study was to determine the levels of AFM1 in UHT milk samples in Central Anatolia, Turkey. The occurrence of AFM1 contamination in UHT milk samples was investigated by ELISA (Enzyme Linked Immunosorbent Assay) technique. A total of 129 samples of commercial UHT whole milk were analysed. The mean value was 108.17 ng/L. There was a high incidence rate of AFM1, with 75 (58.1%) milk samples being contaminated. Although 68 (53%) were below the limit, the remaining 61 (47%) were well above the limit permitted by the EU. Four of the samples exceeded the prescribed limit of US regulations. It can be concluded that AFM1 levels in the samples purchased in Central Anatolia Region, appear to be a serious public health problem at the moment. Dairy farmers must be educated by the government authorities on potential health consequences of aflatoxins.

An electrochemical immunosensor for aflatoxin M1 determination in milk using screen-printed electrodes

The production and assembling of disposable electrochemical AFM1 immunosensors, which can combine the high selectivity of immunoanalysis with the ease of the electrochemical probes, has been carried out. Firstly immunoassay parameters such as amounts of antibody and labelled antigen, buffer and pH, length of time and temperature of each steps (precoating, coating, binding and competition steps) were evaluated and optimised in order to set up a spectrophotometric enzyme-linked immunosorbent assay (ELISA) procedure. This assay exhibited a working range between 30 and 160 ppt in a direct competitive format. Then electrochemical immunosensors were fabricated by immobilising the antibodies directly on the surface of screen-printed electrodes (SPEs), and allowing the competition to occur between free AFM1 and that conjugated with peroxidase (HRP) enzyme. The electrochemical technique chosen was the chronoamperometry, performed at -100 mV. Furthermore, studies of interference and matrix effects have been performed to evaluate the suitability of the developed immunosensors for the analysis of aflatoxin M1 directly in milk. Results have shown that using screen-printed electrodes aflatoxin M1 can be measured with a detection limit of 25 ppt and with a working range between 30 and 160 ppt. A comparison between the spectrophotometric and electrochemical procedure showed that a better detection limit and shorter analysis time could be achieved using electrochemical detection.

Occurrence of aflatoxin M1in 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.

ELISA and HPLC determination of the occurrence of aflatoxin M(1) in raw cow's milk

Raw cow's milk collected from dairy farms in the province of Leon, Spain, was examined for aflatoxin M(1) (AFM(1)). The samples were analysed with a commercial competitive enzyme-linked immunosorbent assay (ELISA) kit and high-performance liquid chromatography (HPLC). The concentrations of AFM(1) in the milk extracts were initially estimated by ELISA, with recovery rates of 74.6-109% for artificially contaminated milk at levels of 10-80 ng x l(1). Samples found to contain more than 10 ng x l(1) were further quantified with HPLC. The mean recovery for this method was 89.3%. The quantification limit was 10 ng x l(1) for both ELISA and HPLC. Although AFM(1) was confirmed in only 3.3% of the samples, the concentrations in all these cases were lower than the maximum limit applicable to these products pursuant to European Union legislation. Both methods were validated with reference material certified by the Community Bureau of Reference.

Occurrence of aflatoxins M(1) and M(2) in milk commercialized in Ribeirão Preto-SP, Brazil

Aflatoxins are toxic metabolites found in foods and feeds. When ruminants eat foodstuffs containing aflatoxins B(1) and B(2), these toxins are metabolized and excreted as aflatoxin M(1) and M(2) in milk. The aim was to determine the incidence of these aflatoxins in commercial milk collected from supermarkets in Ribeirão Preto-SP, Brazil, and consisting of 60 ultrahigh temperature (UHT) milk samples and 79 pasteurized milk samples. The milk samples were analysed according to method 986.16 of AOAC International. None of the milk samples analysed were contaminated with aflatoxin M(2), and aflatoxin M(1) was detected in 29 (20.9%) of samples in the range 50-240 ng l(-1). The results show that despite a high occurrence of aflatoxin M(1) in commercial pasteurized and UHT milk sold in Ribeirão Preto in 1999 and 2000, the contamination level of these toxins could not be considered a serious public health problem according to MERCOSUR Technical Regulations. However, levels in 20.9% of the milk samples exceeded the concentration of 50 ng l(-1) permitted by the European Union. Although it is not necessary to continue monitoring the incidence and levels of aflatoxins M(1) and M(2) in milk samples, surveillance could be appropriate.

Occurrence of aflatoxin M(1) in raw and market milk commercialized in Greece

From December 1999 to May 2000, 114 samples of pasteurized, ultrahigh temperature-treated (UHT) and concentrated milk were collected in supermarkets, whereas 52 raw milk samples from cow, sheep and goat were obtained from different milk producers all over Greece. Sample collection was repeated from December 2000 to May 2001 and concerned 54 samples of pasteurized milk, 23 samples of bulk-tank raw milk and 55 raw milk samples from cow, sheep and goat. The total number of samples analysed for aflatoxin M(1) (AFM(1)) contamination by immunoaffinity column extraction and liquid chromatography was 297. In the first sampling, the incidence rates of AFM(1) contamination in pasteurized, UHT, concentrated and cow, sheep and goat raw milk were 85.4, 82.3, 93.3, 73.3, 66.7 and 40%, respectively, with only one cow raw milk and two concentrated milk samples exceeding the EU limit of 50 ng l(-1). In the second sampling, the incidence rates of AFM(1) contamination in pasteurized, bulk-tank and cow, sheep and goat raw milk were 79.6, 78.3, 64.3, 73.3 and 66.7%, respectively, with only one cow and one sheep raw milk samples exceeding the limit of 50 ng l(-1). The results suggest that the current regulatory status in Greece is effective.

Human exposure to mycotoxins in Egypt

This investigation examined the exposure of Egyptian infants to Aflatoxin M1 (AfM1) and of lactating mothers to Aflatoxin B1, using AfM1 in human milk as a biomarker for exposure to AfB1. The presence of ochratoxin A (OA) in human milk was also investigated to determine the levels of infants exposure to OA from human milk. The results indicated that AfM1 was found in 66 (55 %) of 120 human milk samples with a mean of 0.3 ± 0.53 ng/mL (range 0.02 to 2.09 ng/mL). OA was found in 43 (35.8 %) of 120 human milk samples with a mean of 21.1 ± 13.7 ng/mL (range 5.07 to 45.01 ng/mL), which will cause a daily intake of OA from human milk exceeding the suggested tolerable dose of 5 ng/kg-1 of OA body weight. On the other side AfM1 was found in 25 % of blood samples (5 out of 20 samples), at a mean of 1.18 ng/mL, but it was detected only in one urine sample (1 out of 20 samples). OA was detected only in 2 out of 13 blood samples (15.4 %) with an average 3.67 ng/mL. Whereas OA was not detected in all analyzed urine samples.

Aflatoxin M1 contamination in commercial samples of milk and dairy products in Kuwait

As part of the programme on monitoring of environmental contaminants in food stuff in Kuwait, 54 samples of fresh full cream and skimmed milk, powdered milk, yoghurt, and infant formula were analysed for aflatoxin M1 (AFM1) by HPLC following sample clean up using immuno-affinity columns. Of samples, 28% were contaminated with AFM1 with 6% being above the maximum permissible limit of 0.2 microgl(-1). Three fresh cow milk samples collected from a private local producer showed the highest level of 0.21 microg l(-1) AFM1. There was no contamination with AFM1 in powdered milk and infant formulas. These results show the necessity of a survey involving a larger number of milk and its products and suggest that presently the contamination of milk and milk products with AFM1 does not appear to be a serious health problem in Kuwait. Nevertheless, a continuous surveillance programme may be warranted to monitor regularly the occurrence of aflatoxins in the animal feeds responsible for current limited contamination and to note rapidly and worsening in the situation that may depend on market changes or on unfavourable climatic developments.

Aflatoxin M1 in raw and ultra high temperature-treated milk commercialized in Portugal

During June to September 1999, 31 samples of raw milk were obtained from individual farms and 70 samples of ultrahigh-temperature-treated (UHT) milk (18 samples of whole milk, 22 of semi-skimmed and 30 samples of skimmed milk) were collected in supermarkets in Lisbon, Portugal. The total number of samples analysed was 101. The incidence of aflatoxin M1 (AFM1) contamination in the milk samples analysed was very high (83.2%). AFM1 was detected in 80.6% of raw milk and 84.2% of UHT milk. Concerning raw milk, 17 samples (54.8%) contained low levels (0.005-0.010 microgram/l), two samples (6.5%) had levels ranging from 0.011 to 0.020 microgram/l and six samples (19.3%) had levels between 0.021 and 0.050 microgram/l. Of 70 samples of UHT milk analysed, 10 samples had levels below 0.005 microgram/l (one whole milk, two semi-skimmed milk and seven skimmed milk). Nine samples--two whole milk (11.1%) and seven skimmed milk (23.3%)--were contaminated with levels between 0.005 and 0.010 microgram/l. Twenty-five samples (eight whole milk, 44.4%; one semi-skimmed milk, 4.5%; and 16 skimmed milk, 53.4%) had AFM1 contamination levels of 0.011-0.020 microgram/l. Six samples of whole milk (33.3%) and 18 samples of semi-skimmed milk (81.9%) had levels of 0.021-0.050 microgram/l. Only two samples were contaminated at levels above the legal limit for AFM1 (one whole milk and one semi-skimmed milk, 0.059 and 0.061 microgram/l, respectively). At the moment, the contamination of milk with AFM1 does not appear to be a risk to public health, although the presence of this toxin was detected in 83.2% of the samples analysed.

Application of the assay of aflatoxins by liquid chromatography with fluorescence detection in food analysis

HPLC using fluorescence detection has already become the most accepted method for the determination of aflatoxins due to its several advantages over other analytical methods. Both normal- and reversed-phase HPLC can be used. However the reversed-phase HPLC methods are more popular. Liquid chromatographic determination of aflatoxins using fluorescence detection and its application in food analysis is reviewed in this article.

Situation of mycotoxins in milk, dairy products and human milk in Egypt

ABSTACT: Milk and dairy products purchased at Egyptian markets and breast milk from lactating mothers in Cairo and Giza governorates were analyzed for some mycotoxins. Three of 15 cows' milk samples were found positive for Afl. M1 with mean value 6.3 ppb. Only one sample of dried milk was positive (5 ppb). Two of 10 hard cheese samples contained detectable levels of Afl. M1 (3and 6 ppb), whereas one sample containing Afl. B1 and G1 (10 and 4 ppb resp.). For soft cheese one sample of 10 was positive for Afl. M1 (0.5 ppb). Blue veined cheeses were free of Afl. M1 and PR-toxins.For breast milk two of 10 samples were positive for Afl. M1 (20%) with mean value 2.75 ppb, while 3 of 10 samples were positive for Ochratoxin A (30 %).

Occurrence of aflatoxin M1 in Korean dairy products determined by ELISA and HPLC

The occurrence of aflatoxin M1 (AFM1) in pasteurized milk and dairy products was investigated by using direct competitive enzyme-linked immunosorbent assay (ELISA) and high-performance liquid chromatography (HPLC). The recoveries of AFM1 from the samples spiked at levels between 5 and 500 pg/ml were 88.0-106.5% for pasteurized milk and 84.0-94.0% for yoghurt by ELISA. By HPLC, the recoveries were 103-120% for pasteurized milk and 87.0-93.0% for yoghurt. The limits of detection were found to be 2 pg/ml by ELISA and 10 pg/ml by HPLC. Among a total of 180 samples collected in Seoul, Korea, the incidence of AFM1 in pasteurized milk, infant formula, powdered milk and yoghurt was 76, 85, 75, and 83%, respectively, with a mean concentration of 18, 46, 200, and 29 pg/g, respectively, when determined by ELISA. These results obtained by ELISA were closely related to those by HPLC for AFM1 (r2 = 0.9783).