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PubMedDate not supplied

Aflatoxin M1 occurrence in dairy products marketed in Italy.

In 1984, 313 samples of imported liquid milk and 159 samples of imported cheese were checked for aflatoxin M1; 225 of the milk samples came from FR Germany and 88 from France, while 82 of the cheese samples came from France, 34 from FR Germany and 43 from the Netherlands. The number of positive samples was small both for German (13.8%) and for French (12.5%) milks, and the contamination levels were very low (maximum 23 ng/l). As regards the cheeses, aflatoxin M1 was detected in 19.5, 26.5 and 53.5% of the French, German and Dutch samples respectively, but only 2 French samples exceeded 250 ng/kg, the limit set by Swiss law. In 1985, two surveys were carried out on 276 milk samples mostly obtained from individual farms and on 416 cheese samples taken from all parts of the country. As regards the milk samples, 70 (25.3%) contained aflatoxin M1, but generally at very low levels; in fact only 7 (2.5%) of the samples exceeded 50 ng/l. Aflatoxin M1 was found in 130 (31.3%) of the cheese samples, but here again only 9 (2.2%) exceeded 250 ng/kg. There was no significant difference in aflatoxin M1 levels between Italian, German and French cheese samples but these were significantly lower (P less than 0.01) than in Dutch samples.

Aflatoxin M1↗
PubMed2005

Head space sensor array for the detection of aflatoxin M1 in raw ewe's milk.

A novel screening method was developed for simple and rapid detection of aflatoxin M1 contamination in raw ewe's milk samples without the need for sample pretreatment. The method was based on the use of a commercial head space sensor array system constituted by 12 metal oxide semiconductor sensors, 10 metal oxide semiconductor field-effect transistor sensors, and a pattern recognition software. Twenty-four raw milk samples collected from two different groups of ewes fed with a formulated feed that contained increasing amounts of aflatoxin B1 and six noncontaminated ewe's milk samples were analyzed. The results obtained by using the head space sensor array, processed by statistical methods, made it possible to group the samples according to the presence or the absence of aflatoxin M1. Sample classification was in complete agreement with the aflatoxin M1 content measured by an enzyme-linked immunosorbent assay procedure. This is the first report, to our knowledge, of detection of aflatoxin M1 in ewe's milk by a multisensor array.

Aflatoxin M1↗
PubMed1984

Effects of aflatoxin M1 intake at physiologic levels on newborn dairy calves.

When aflatoxin-contaminated grain is consumed by dairy cows, aflatoxin M1 is excreted in the milk. Sixteen neonatal male Holstein calves were given milk which had been collected from cows given 5 to 6 mg of aflatoxin B1 each day. The calves were examined for possible detrimental effects of the mycotoxin at pseudophysiologic concentrations. Calves were allotted to 1 of 4 groups given different milk dietary aflatoxin M1 concentrations: group 1--given 0 microgram of aflatoxin M1/L (undetectable); group 2--given 0.5 microgram/L; group 3--given 1 microgram/L; and group 4--given 2 micrograms/L. Whole milk equal to 8% of body weight was fed daily and adjusted each week to maintain this ratio. Water and a 15% crude protein complete calf starter ration were offered ad libitum for the 6-week feeding study. Weekly blood samples were collected via jugular venipuncture and analyzed for serum alkaline phosphatase and aspartate aminotransferase activities. Daily means for milk dry matter intake (in kg) and complete ration intake (in kg) for the calf groups were as follows: 0.46 and 0.36 for group 1; 0.46 and 0.25 for group 2; 0.42 and 0.18 for group 3; and 0.49 and 0.40 for group 4. Significant differences in complete ration and total dry matter intake were noted. The average daily gains (in kg) and gains in height at withers (in cm) were 0.39 and 4.1 for group 1; 0.36 and 4.0 for group 2; 0.29 and 5.7 for group 3; and 0.42 and 5.1 for group 4.(ABSTRACT TRUNCATED AT 250 WORDS)

Aflatoxin M1↗
PubMed1977

[Determination and occurence of aflatoxin M1 and B1 in milk and dairy products].

The described method enables a simultaneous identification and determination of aflatoxin M1 and B1 in milk and dairy products by means of a self-registering fluorescence spectrophotometer with a thin-layer chromatographic accessory, directly from the plate. The semiquantitative estimation on the thin-layer chromatographic plate enables also routine analyses in the hygienic practice. The recovery rates for aflatoxin M1 and B1 in milk are about 83 and 82%, respectively -- the detection limit is about 0.1 microng per kg. The recovery rates for aflatoxin M1 and B1 in milk powder are about 89 and 94%, respectively -- the detection limit is bout 0.5 microng per kg. The reproducibility is given with a standard deviation between +/- 1.1 and 6,3% and a variation coeffecient of 1.3 and 6.7, respectively. 4 of 24 analized samples of commercial winter milk were aflatoxin M1-positive, whereas aflatoxin B1 could not be found. One of the milk powder products, a sample of the infant food, "Ki-Na", made in the GDR, contained, however aflatoxin B1. Aflatoxin M1 could not be found. Food-hygienic-toxicological conclusions are discussed.

Aflatoxins↗
PubMed1988

Presence of aflatoxin M1 in commercial ultra-high-temperature-treated milk.

Forty-seven samples of commercial ultra-high-temperature-treated milk from a dairy facility in the northwest part of Spain were analyzed for the presence of aflatoxin M1. A total of 14 samples (29.8%) were positive for aflatoxin M1 (4 in May, 3 in November, 3 in December, 1 in January, 1 in April, 1 in July, and 1 in August), 29 (61.7%) were negative, and 4 (8.5%) were doubtful, i.e., they showed trace quantities of aflatoxin M1. The range of aflatoxin M1 content was 0.02 to 0.1 ng/ml.

Aflatoxin M1↗
PubMedDate not supplied

Methods for determination of aflatoxin M1 in milk and milk products--a review of performance characteristics.

Among numerous methods that have been published for determination of aflatoxin M1 in milk and milk products, the following have been selected for review of performance characteristics: methods for which interlaboratory testing has been carried out, methods proposed in support of national (Swiss) regulations following inclusion in check sample series, and methods that report detection limits for milk of less than or equal to 5 ng/l (less than or equal to 0.005 microgram/l) or less than or equal to 10 ng/kg (less than or equal to 0.01 microgram/kg) for cheese. It is practical to determine aflatoxin M1 in milk with good accuracy and precision down to low ng/l concentrations using thin-layer chromatography, high-performance liquid chromatography or enzyme-linked immunosorbent assay for quantitation. However, measurement at such low levels has not been tested by a true collaborative study. Confirmation of identity of aflatoxin M1 at low ng/l levels has also been reported. Recent evidence suggests that consideration should be given to inclusion of aflatoxin M4 in methods for aflatoxin M1.

Aflatoxin M1↗
PubMed1985

Cancer risks posed by aflatoxin M1.

The suspect milk-borne carcinogen, aflatoxin M1 (AFM), was produced and isolated from the rice culture of the fungus Aspergillus flavus NRRL3251 for confirmation and determination of the potency of its carcinogenicity in the male adult Fischer rat. The carcinogen was mixed into an agar-based, semisynthetic diet at 0, 0.5, 5, and 50 ppb (microgram/kg) and was fed to groups of animals continuously for 19-21 months. Aflatoxin B1 (AFB), of which AFM is a metabolite, at 50 ppb was used as a positive control. Hepatocarcinogenicity of AFM was detected at 50 ppb, but not at 5 or 0.5 ppb, with a potency of 2-10% that of AFB. A low incidence of intestinal adenocarcinomas was found in the AFM 50 ppb group, but not in any other groups. At 0.5 ppb, the action level enforced by the U.S.A. Food and Drug Administration, AFM induced no liver lesions in the rats but stimulated the animals' growth. On the average, the rats in the 0.5 ppb group weighed 11% (p less than 0.001) more than those in the control group. This increased growth was associated with increased feed intake. Based on the biological activity of AFM at the relevant low doses and the estimated level of human exposure to AFM through consumption of milk, the cancer risk posed by this contaminant for human adults is assessed to be very low. For infants, further studies are warranted because milk constitutes the major ingredient of the infant diet and because infant animals have been shown to be more sensitive to the carcinogenicity of AFB than adult animals.

Aflatoxin M1↗
PubMedDate not supplied

Development of milk powder reference materials certified for aflatoxin M1 content (Part II): Certification of milk powder RM 283.

The development of a full cream milk powder reference material, certified for its aflatoxin M1 content (target concentration: 0.1 microgram/kg), is described. The material (RM 283) was prepared and certified within the Reference Material Programme of the Community Bureau of Reference, along with other members of a series of milk powder reference materials. Homogeneity, evaluated by determining the aflatoxin M1 content of 30 units, was found to be acceptable (coefficient of variation of analysis results: 9.1%); stability has been demonstrated in a long-term study. The certification exercise involved 7 laboratories. Calibration, control of recoveries, blank values, and independence of the replicate measurements were emphasized. All sets of results of the certification exercise were accepted for statistical evaluation. A certified value for the aflatoxin M1 content: 0.09(+0.04)(-0.02) micrograms/kg was derived. The certification of RM 283 completes the series of 4 milk powder reference materials having certified aflatoxin M1 contents.

Aflatoxin M1↗
PubMed2003

Excretion of aflatoxin M1 in milk of dairy ewes treated with different doses of aflatoxin B1.

Two experiments were conducted to study the amount of aflatoxin M1 (AFM1) in milk in response to feeding aflatoxin B1 (AFB1). In experiment 1, four dairy ewes in early lactation received a single dose of pure AFB1 (2 mg). Individual milk samples were collected during the following 5 d to measure AFM1 concentration. The average excretion of AFM1 in milk followed an exponential decreasing pattern, with two intermediate peaks at 24 and 48 h. No AFM1 was detected in milk at 96 h after dosing. The mean rate of transfer of AFB1 into AFM1 in milk was 0.032%, with a high individual variability (SD = 0.017%). In experiment 2, 16 dairy ewes in midlactation were divided into four groups that received different daily doses of AFB1 (0, 32, 64, and 128 microgram for control and groups T1, T2, and T3, respectively) for 14 d. Pure AFB1 was administered to each animal divided in two daily doses. Individual milk samples were collected at 12, 24, 36, 48, 72, 96, 144, 216, and 312 h after the first AFB1 administration, during the intoxication period, and every 24 h for 7 d after the withdrawal of AFB1. AFM1 was detected in the milk of all animals of the treated groups at 12 h after the administration of AFB1. In all treated groups, milk AFM1 concentration increased from 12 to 144 h after the beginning of administration. It then decreased, reaching a stable concentration at 216 and 312 h after the first administration. No AFM1 was detected in milk 3 d after the last administration of AFB1. Milk AFM1 concentration measured at steady-state condition was significantly affected by the AFB1 dose (0.031, 0.095, and 0.166 in T1, T2, and T3 groups, respectively), with a linear relationship between AFB1 dose and milk AFM1 concentration (R2 = 77.2%). The carryover (AFM1/AFB1 ratio) was not significantly affected by treatment, and its mean value was 0.112% (SE = 0.011). The carryover was lower than that reported for dairy cattle and goats, suggesting a better ability of sheep to degrade AFB1.

Aflatoxin B1↗
PubMed1998

[Determination of selected mycotoxins in food. I. Selection of optimal conditions for the determination of aflatoxin M1 in milk using high-performance liquid chromatography methods].

The aim of this study was to perform a optimized method for determination of aflatoxin M1 in milk. The manner of extraction and clean-up of milk extracts as well conditions of reaction of aflatoxin M1 with TFA and HPLC was described. The main steps of optimized method were: extraction of samples with chloroform, clean-up of extracts on SPE C18 columns and by means of extraction with n-hexane, derivatisation of aflatoxin M1 with TFA (60 degrees C, 6 minutes) to acetal form--aflatoxin M2a and determination of aflatoxin by means of the RP-HPLC technique. The mobile phase was a mixture of methanol, isopropanol and water (18 + 7 + 75). Fluorometric detection was made at 370/418-700 nm. The mean recovery of aflatoxin M1 dependent on fortification level was 62-67%, limit of detection was 0.01 microgram/1 of milk.

Aflatoxin M1↗
PubMedDate not supplied

Rapid reverse phase liquid chromatographic determination of aflatoxin M1 in milk.

A rapid, economical, and reliable liquid chromatographic (LC) method is described for determination of aflatoxin M1 in milk. The method includes an improved AOAC extraction procedure, cleanup of the extract on a silica cartridge, and LC quantitation. Alternatively, a rapid column cleanup procedure can be used. Milk artificially spiked with aflatoxin M1 at 0.05, 0.1, and 0.5 ppb was analyzed using both new approaches as well as an AOAC method coupled with LC for quantitation of the toxin. Recovery of aflatoxin M1 by the first approach of the new method ranged between 93.4 and 99.1%, and for the alternative procedure between 92.4 and 96.8%. The AOAC method gave lower recovery (85.6-90.7%) of toxin, but the results from this method had a somewhat smaller standard deviation for replicate analyses than did results of the new method.

Aflatoxin M1↗
PubMedDate not supplied

Production and isolation of aflatoxin M1 for toxicological studies.

One hundred mg aflatoxin M1 was produced and purified for toxicological studies. Aspergillus flavus NRRL 3251 was cultured on rice to produce aflatoxins B1, B2, M1, and M2, B1 and B2 were separated from M1 and M2 by a normal phase low pressure liquid chromatography (LC) column. M1 was then separated from M2 by a reverse phase low pressure LC column. Recoveries of aflatoxins from the LC columns were about 90%. The purified M1 was confirmed by ultraviolet-visible spectrometry, mass spectrometry, nuclear magnetic resonance spectrometry, optical rotation, and its mutagenicity to Salmonella typhimurium TA98.

Aflatoxin M1↗
PubMed2006

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.

Aflatoxin M1↗
PubMed1980

[Aflatoxin M1 in milk and milk products. A comparison of some determination procedures].

Usual TLC-methods for the determination of Aflatoxin M1 in milk and milk products sometimes do not separate interfering substances with similar optical and chemical properties from Aflatoxin M1, thus leading to considerably incorrect results. Even after an additional clean-up on polystyrene column the solutions contain so many compounds that the identification of Aflatoxin M1 is difficult. The resolving power of HPLC yield pure frations, which may be determined by their MS and UV spectra.

Aflatoxin M1↗
PubMedDate not supplied

Aflatoxin M1 8,9-epoxide: preparation and mutagenic activity.

Treatment of aflatoxin M1 (AFM1) with dimethyldioxirane in an anhydrous mixture of CH2-Cl2 and acetone afforded the corresponding aflatoxin M1 8,9-epoxide (AFM1-E) in practically quantitative yield. This highly reactive intermediate was identified by 1H NMR and characterized by its neat conversion into the corresponding trans-methoxyhydrin derivative 1. The analysis of the 1H NMR spectrum of the above epoxide revealed that one stereoisomer, which should be that with the exo configuration, was present as major component. The mutagenicities of AFM1-E, the parent mycotoxin (AFM1), aflatoxin B1 (AFB1), and its epoxide (AFB1-E) were assessed by using a sensitive improved Ames test with the Salmonella typhimurium strain TA-100. AFM1 and AFB1 had specific mutagenic activities (SMA) of 13 and 121 revertants/ng, respectively, with S9 metabolic activation. AFM1-E was mutagenic with and without metabolic activation showing SMA of 13 and 12 revertants/ng, respectively. AFB1-E had a SMA of 42 and 29 revertants/ng, with and without S9 metabolic enzymes, respectively. These results suggest that the epoxidation of AFM1 can constitute a major route accounting for the cytotoxic effects elicited by this mycotoxin and that AFM1-E is not as active as AFB1-E in reacting with the constituents of the mutagenicity assay.

Aflatoxin M1↗
PubMedDate not supplied

A survey of the occurrence of aflatoxin M1 in UK-produced milk for the period 1981-1983.

A UK survey for the occurrence of aflatoxin M1 in bulked dried milks (totalling 277 samples) obtained at monthly intervals from a number of commercial creameries in the UK over a two-year period (1981-1983), showed 98% of the samples to have levels below 0.03 micrograms/kg. For liquid milks sampled from individual farms over the same period (totalling 409 samples), 94% of the samples had aflatoxin M1 levels below 0.01 micrograms/kg. All samples were initially screened by a two-dimensional thin layer chromatographic method and quantification of positive results was by reverse phase h.p.l.c. with fluorescence detection. The results of this survey show that UK milk is largely free of aflatoxin M1 contamination, the incidence and levels, where observed, being significantly lower than for other European countries, which demonstrates the effectiveness of UK legislative action controlling feedstuff contamination.

Aflatoxin M1↗
PubMedDate not supplied

Rapid liquid chromatographic determination of aflatoxins M1 and M2 in artificially contaminated fluid milks: collaborative study.

An international collaborative study involving 14 collaborators from 5 different countries was conducted to test a rapid liquid chromatographic (LC) method for detecting aflatoxins M1 and M2 in fluid milk. Each collaborator prepared artificially contaminated milk samples (0.078-1.31 ng M1/mL and 0.030-0.13 ng M2/mL) by adding solutions containing various concentrations of aflatoxins M1 and M2 to fresh milk. Recoveries ranged from 85.2 to 102.5% (av. 93.7%) for aflatoxin M1 and from 99.5 to 126.7% (av. 109.8%) for aflatoxin M2. Coefficients of variation averaged 21.4% (M1) and 35.9% (M2). An analysis of variance was calculated from combined data to determine variance components. The within-laboratory variations (So) (repeatability) were 27.9% (M1) and 23.9% (M2), and the among-laboratory variations (Sx) (reproducibility) were 44.5% (M1) and 64.7% (M2). No visual differences were determined between normal or reverse phase LC for contaminated samples; however, there were an insufficient number of collaborators using normal phase to give meaningful separate statistical data. For 26 observations of uncontaminated milk, 3 false M1 positives were reported for normal phase LC determinations and 2 false M1 positives were reported for reverse phase LC determinations. Three normal phase and 11 reverse phase false M2 positives were reported for 104 observations in uncontaminated milk. The reverse phase LC method for determination of aflatoxins M1 and M2 in fluid milk has been adopted official first action.

Aflatoxin M1↗
PubMedDate not supplied

Exposure of infants to aflatoxin M1 from mothers' breast milk in Abu Dhabi, UAE.

During a survey of the occurrence of aflatoxins in mothers' breast milk carried out in Abu Dhabi, involving 445 donors at the Cornich Hospital and the Al Nehyan Clinic for Maternity and Childhood, 99.5% of samples were found to contain aflatoxin M1 at concentrations ranging from 2 pg ml-1 to 3 ng ml-1. The mothers represented a wide range of nationalities, ages and health status and the opportunity was used to seek any correlation between these factors and the concentration of aflatoxin M1 in breast milk. The protein, fat and lactose contents of milk samples were also determined and the possibility of any correlation between any of these and aflatoxin M1 was studied.

Adolescent↗