AFM1 Levels Research Articles

Aflatoxin M1 levels in butter and cream cheese consumed in Turkey

In this study, 92 butter and 100 cream cheese samples were analyzed for aflatoxin M1 (AF M1). They were obtained from retail outlets in five big cities (Istanbul, Izmir, Kayseri, Konya, Tekirdag). The occurrence and concentration range of AF M1 in the samples were investigated by competitive enzyme-linked immunosorbent assay (ELISA) method using immunoaffinity columns. At the detectable level of 10 ppt all 100% of the butter samples and 99% of the cream cheese samples contained AF M1. The incidence of AF M1 in the butter samples and the cream cheese samples ranged from 10 to 7000 ng/kg and from 0 to 4100 ng/kg, respectively. AF M1 levels in 28% of the butter and 18% of the cream cheese samples exceeded the maximum tolerable limit of the Turkish Food Codex. AF M1 levels in the samples show that there is a presence of high aflatoxin level that constitutes a human health risk in Turkey. Therefore farmers and dairy companies need to be informed about the aflatoxin and aflatoxicosis, and also the continuous monitoring of the aflatoxin level must be applied by the Turkish public health authorities.

A longitudinal assessment of aflatoxin M 1 excretion in breast milk of selected Egyptian mothers

Aflatoxins are potent toxins and carcinogens which can be excreted in the milk of exposed lactating mothers mainly in the form of aflatoxin M 1 (AFM 1). We previously evaluated the level and frequency of AFM 1 in breast milk in a group of Egyptian mothers attending the New El-Qalyub Hospital, Qalyubiyah governorate, Egypt. In this study, fifty of those women who were AFM 1 positive were revisited monthly for 12 months to assess the temporal variation in breast milk AFM 1. AFM 1 was detected in 248 of 443 (56%) samples. In a multilevel model of the data there was a highly significant ( p < 0.001) effect of month of sampling on the frequency of AFM 1 detection with summer months having the highest frequency (>80%) and winter months the lowest frequency (<20%) of detection. AFM 1 was observed most frequently in June [OR 63, 95% CI (7.6, 522)]. The level of AFM 1 detection also followed this seasonal pattern with highest mean level in July (64 pg/ml milk, range 6.3–497 pg/ml milk) and the lowest mean level in January (8 pg/ml milk, range 4.2–108 pg/ml milk). The duration of lactation [ p = 0.0035, OR = 1.08, 95% CI (1.02, 1.13)], and peanut consumption [ p = 0.06, OR = 1.69, 95% CI (0.9, 2.9)] also contributed to the model. The identification and understanding of factors determining the presence of toxicants in human milk is important and may provide a knowledge driven basis for controlling the transfer of chemicals to infants.

Presence of aflatoxin M 1 in milk and infant milk products in Tehran, Iran

Aflatoxins are highly toxic, mutagenic, teratogenic and carcinogenic compounds. The purpose of this survey was to determine natural occurrence and level of AFM 1 in pasteurized liquid milk, infant formula and milk-based cereal weaning food consumed in Tehran, Iran. A total of 328 branded milk products and liquid milk samples were collected and investigated by Enzyme Linked Immuno Sorbent Assay (ELISA). The samples of pasteurized liquid milk ( n = 128), infant formula ( n = 120) and milk-based cereal weaning food ( n = 80) showed that the incidence of contamination with AFM 1 is 96.3%, the presence of AFM 1 in each group was 72.2 ± 23.5, 7.3 ± 3.9 and 16.8 ± 12.5 ng/kg, ranging between 31–113, 1–14 and 3–35 ng/kg, respectively. In general, the amount of AFM 1 in 100 (78%) of liquid milk samples and 24 (33%) of milk-based weaning food was higher than the maximum tolerance limit accepted by European Union, but in all of the infant formula samples was lower (European Communities and Codex Alimentarius has prescribed a limit of 50 ng/kg for AFM 1 in milk and 25 ng/kg in infant milk products).

Determinants of aflatoxin M1 in breast milk in a selected group of Egyptian mothers

In Egypt, there is a paucity of biomarker data on aflatoxin (AF) exposure. The study assessed the level and frequency of breast milk AFM1 as a biomarker of maternal exposure. Breast milk samples were collected from a selected group of 388 Egyptian lactating mothers of children attending the New El-Qalyub Hospital, Qalyubiyah governorate, Egypt, during May–September 2003. Following aflatoxin extraction, AFM1 levels were assessed by high-performance liquid chromatography (HPLC) with fluorescence detection. Approximately 36% of mothers tested positive for AFM1 (median 13.5 pg ml−1, interquartile range (IQR) 10.27–21.43). Non-working status (p = 0.018, odds ratio (OR) = 2.87), obesity (p = 0.004, OR = 3.01), high corn oil consumption (p = 0.002, OR = 2.21), number of children (>1) (p = 0.025, OR = 1.99), and early lactation stage (<1 month) (p = 0.028 OR = 3.57), contributed to the occurrence of AF in breast milk. AFM1 contamination of breast milk was frequent, albeit at moderate levels. Growth and development of the infant is rapid and thus it is possible that AF exposure through breast milk has a significant health effect.

A study on the occurrence of aflatoxin M 1 in Iranian Feta cheese

This study was undertaken to determine the presence and levels of aflatoxin M 1 (AFM 1) in cheeses produced by different plants in the province of Tehran. For this purpose, a total of 80 cheese samples analyzed, and thin layer chromatography (TLC) was used to determine the presence and levels of AFM 1. AFM 1 was found in 82.5% of 80 of the cheese samples examined. The range of contamination levels varied among different months. AFM 1 in May, August, November, February samples ranged from 0.17 to 1.30, 0.15 to 2.41, 0.16 to 1.11, and 0.19 to 2.05 μg/kg, respectively, while the mean values were 0.41, 0.35, 0.36, and 0.52 μg/kg, respectively. The highest mean concentration of aflatoxin M 1 (AFM 1) was registered in February samples (0.52 μg/kg). The lowest mean concentration of aflatoxin M 1 was registered in August samples (0.35 μg/kg). Statistical evaluation showed that there were not significant differences ( P > 0.05) between the concentrations of AFM 1 of cheese samples taken in May and August with November and February. In other words, AFM 1 contents of cheese samples taken in November and August were not lower than cheese samples taken in May and February. Almost 60.6% of the contaminated samples exceeded the maximum acceptable levels (0.25 μg/kg) that accepted by some of the countries such as Turkey. It was therefore concluded that, high occurrence of AFM 1 in cheese samples were considered to be possible hazards for human health.

Detection of aflatoxin M 1 in cheese samples by ELISA

This study was undertaken to determine the presence and levels of aflatoxin M 1 (AFM 1) in cheeses consumed in the province of Ankara. For this purpose, a total of 400 cheese samples containing 100 samples each of white, kashar, tulum and processed cheeses were used as the study material. The cheese samples were purchased randomly from different markets. The competitive ELISA (RIDASCREEN Aflatoxin M 1, no. R1101) was used to determine the presence and levels of AFM 1. Different levels of AFM 1 were detected in the 327 (81.75%) cheese samples consisting of white (82%), tulum (81%), kashar (85%) and processed cheese (79%) samples. Altogether, 110 cheese samples (27.5%) were found to have levels that exceed the legal limits of 250 ng/kg established by the Turkish Food Codex. Among these, 27% of white cheese, 24% of tulum cheese, 34% of kashar cheese and 25% of processed cheese exceeded the Turkish safety limits. It was therefore concluded that, widespread occurrence of AFM 1 in cheese samples sold in the Ankara province were considered to be possible hazards for human health.

Development and application of an indirect competitive enzyme-linked immunoassay for aflatoxin m(1) in milk and milk-based confectionery.

High-titer rabbit polyclonal antibodies to aflatoxin M(1) (AFM1) were produced by utilizing AFM1-bovine serum albumin (BSA) conjugate as an immunogen. An indirect competitive enzyme-linked immunosorbent assay was standardized for estimating AFM1 in milk and milk products. To avoid the influence of interfering substances present in the milk samples, it was necessary to prepare AFM1 standards in methanol extracts of certified reference material (CRM) not containing detectable AFM1 (< 0.05 ng/g). The reliability of the procedure was assessed by using CRM with AFM1 concentrations of < 0.5 and 0.76 ng/g. Also, assays of milk samples mixed with AFM1 ranging in concentration between 0.5 and 50 ng/L gave recoveries of > 93%. The relative cross-reactivity with aflatoxins (AF) and ochratoxin A, assessed as the amount of AFM1 necessary to cause 50% inhibition of binding, was 5% for AFB1 and much less for AFB2, AFG1, and AFG2; there was no reaction with ochratoxin A. AFM1 contamination was measured in retail milk and milk products collected from rural and periurban areas in Andhra Pradesh, India. Of 280 milk samples tested, 146 were found to contain < 0.5 ng/mL of AFM1; in 80 samples it varied from 0.6 to 15 ng/mL, in 42 samples from 16 to 30 ng/mL, and in 12 samples from 31 to 48 ng/mL. Most of the milk samples that contained high AFM1 concentrations were obtained from periurban locations. The results revealed a significant exposure of humans to AFM1 levels in India and thus highlight the need for awareness of risk among milk producers and consumers.

Incidence of aflatoxins B1 and M1 in raw milk and some cheeses

A tolal of 150 random samples of market raw cows milk, hard chesse, and processed cheese (50 each) were collected from different groceries and supermarkets at Mansoura city, and investigated for the presence of aflatoxins B1 and/or M1 as well as the thermostability of both toxins against laboratory pasteurization of contaminated milk samples at 63°c for 30 min. One hundred and twenty one (80.66%) of 150 samples were contaminated with aflatxin(s), 35 (23.33%) samples were polluted with AFB1 alone, 33 (22.00%) samples had AFM1 alone, and 53(35.33%) samples contained AFB1 and AFM1. Of all examined samples, 35(70%) milk, 45 (90%) hard chesse, and 41(82%) processed cheese samples were contaminated with aflation (s). The averages of AFBI and AFM1 levels were 1.06±0.23 and 1.16±0.20µg/L of milk, 7.54±1.46 and 3.88±0.90 µg/kg of hard chesse, and 13.11±2.70 and 14.06±2.36 µg/kg of processed chesse samples, respectively. All contaminated cheese samples contained AFB1 and/or AFM1 by levels more than both Egyptian and FDA limits (nil and 0.5 µg/kg for each toxin), while 20 (40%) and 21 (42%) of aflatoxin- contaminated raw milk samples harboured toxin quantities higher than FDA limits for AFB1 and AFM1 consecutively (0.5 µg/L for each toxin. As regards the effect of pasteurization of aflatoxin- contaminated milk samples at 63oc for 30 min., there were a negligible percentages of reductions ranged from 4.9 to 7.8% for AFB1 and 0.6 to 3.1% for AFM1. Public health significance of recognized aflatoxins as well as a suggested measures for minimizing or resolving such a world wide problem were discussed.

Distribution of aflatoxin M1 in cheese obtained from milk artificially contaminated

Small-scale manufacture of cheese using artificially AFM1 contaminated milk as raw material to study the distribution of such toxin both in whey and in cheese, was carried out. Whole milk with undetectable levels of AFM1 was used. The toxin was added in concentration that varied from 1.7 to 2.0 μg/l of milk. After the home-made production of cheese, the concentration of AFM1 was determined both in whey and in cheese, using the enzymatic immunoassay technique. The greatest proportion, 60%, was detected in whey while 40% AFM1 remained in cheese.

Aflatoxin M1 occurrence in samples of Grana Padano cheese

A total of 223 samples of Grana Padano cheese manufactured in 4 years (1991–94) by dairies in 11 provinces of the Po valley were checked for aflatoxin M1. Grated cheese was extracted with chloroform and the defatted extract was purified by an immunoaffinity column; aflatoxin M1 was determined by HPLC using a fluorescence detector. From the analysis of the data it has emerged that only one sample exceeded the maximum tolerated level in cheese in some European countries (250 ng/kg). Most samples (91%) were in the range 5–100 ng/kg and only 15 (6.7%) in the range 100–250 ng/kg. Notwithstanding a diffuse microcontamination, the situation regarding the AFM1 levels can be considered fairly satisfactory. Mean contamination levels of 1992 and 1994 were significantly higher (P < 0.05) than those of 1993 and 1991. No significant difference was observed among provinces or dairies of origin.

Aflatoxin M 1 in human breast milk samples from Victoria, Australia and Thailand

This study examined the exposure of infants to aflatoxin M 1 (AFM 1) and of lactating mothers to aflatoxin B 1 (AFB 1), using AFM 1 in breast milk as a biomarker for exposure to AFB 1. An enzyme-linked immunosorbent assay was modified for the analysis of AFM 1 in breast milk samples from 73 women from Victoria for comparison with breast milk samples from Thailand ( n = 11). The results were compared with those obtained by HPLC. AFM 1 was detected in 11 samples from Victoria and five samples from Thailand at median concentrations of 0.071 ng/ml (range 0.028 to 1.031 ng/ml) and 0.664ng/ml (range 0.039 to 1.736 ng/ml), respectively. Levels of AFM 1 in Thai milk samples were significantly higher than those in milk samples from Victoria.

Carry-over of aflatoxin from cows' food to milk

AbstractTwo experiments were made. In experiment 1, dairy cows in early lactation (2 to 4 weeks) and dairy cows in late lactation (34 to 36 weeks) were given aflatoxin B, (AFBt)at a level of 34 to 39 fig/day by feeding them contaminated compound food. The aflatoxin Mrcontent(AFMj) of raw milk was determined four times during the experimental period of 14 days. The milk yield was measured daily.The carry-over rate of aflatoxin was proportionately 0·062 and 0·018 for cows in early and late lactation respectively. This difference was not only due to milk production level but possibly also associated to AFB, liver metabolism.In experiment 2, eight high (40 kg milk per day) and eight low (16 kg milk per day) milk yielding cows, carry-over of AFB1 from compound food into AFM, in milk was measured at different levels ofAFB7 intake ranging from 7 to 57 fig/day. Independent of AFBj-intake, high-producing dairy cows had a higher carry-over rate than low producing animals (proportionately 0·038 v. 0·025). Carry-over ofAFB1 to AFM, was linearly correlated with milk yield. Variations in the level of AFM1 in milk of individual cows were not due to variations in milk yield. The relationship between AFB2 intake per day and AFM^content in milk per kg could be described by the formula: AFMj (ng/kg milk) = 119 AFB, intake (fig per cow per day) + 1·9. This means that in order to produce milk with less than 0·05 fig AFM, per kg milk the average daily individual intake in a herd should be limited to 40 fig AFB7 per day.As dairy cows in their early to mid lactation period consume large quantities of compound food, a maximum level of AFB3 in dairy foods has to be set at an acceptable daily intake (ADI) value to guarantee that AFM1 levels in milk do not exceed tolerable levels.

Aflatoxin toxicity in cultured human epidermal cells: stimulation by 2,3,7,8-tetrachlorodibenzo-p-dioxin.

Aflatoxin B1 (AFB1) at 1 microgram/ml was markedly toxic to human epidermal cells grown in the Rheinwald-Green 3T3 feeder layer system. At 0.1 microgram/ml, the toxicity was barely evident, as assessed by colony expansion during a 2 week exposure, but it was dramatically stimulated by 5 nM 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), which was non-toxic alone. Neither AFB1-dihydrodiol nor AFB2 were toxic in the presence or absence of TCDD, indicating that metabolism to the 8,9-epoxide was responsible for the AFB1 toxicity. Stimulation of AFB1 epoxidation by TCDD was also indicated by the > 20-fold increase in DNA adduct formation in cultures exposed to [14C]AFB1 and TCDD for 4 days as compared to AFB1 alone. Analysis of free metabolites in culture medium by reverse-phase HPLC revealed that confluent epidermal cultures metabolized AFB1 to AFM1, AFB2a and aflatoxicol. In the presence of TCDD, the levels of AFM1 were higher (14 versus 3% of dose) as were those of AFB2a (3 versus 0.5% of dose), while aflatoxicol levels were lower (0.8 versus 2% of dose). In the absence of irradiated 3T3, the toxicities of AFB1, AFB2, AFM1 and aflatoxicol to cells in serum-free medium (0.15 mM Ca2+) were similar to those in the feeder layer system. Although this moderately low calcium concentration appeared quite satisfactory for observing toxicity, the response was attenuated at a lower calcium concentration (0.09 mM Ca2+).