Changes in concentration of aflatoxin M1 during manufacture and storage of skim milk powder

In this study, skim milk powder was produced from cow's milk contaminated artificially with aflatoxin M1 (AFM1) at two different levels, 1.5 and 3.5 microg/liter (ppb), and the effects of process stages on the AFM1 contents were investigated. Pasteurization, concentration, and spray drying caused losses of about 16, 40, and 68%, respectively, in AFM1 content of the milk contaminated with 1.5 microg/liter AFM1, and losses of 12, 35, and 59%, respectively, in the milk contaminated with 3.5 microg/liter AFM1. These losses were found to be statisticially significant at the level of P < 0.01. After 3- and 6-month storage periods, AFM1 content of the skim milk powder produced from milk with 1.5 microg/liter AFM1 decreased by 2 and 5%, respectively, whereas these rates were 2 and 4%, respectively, for the skim milk powders made from milk with 3.5 microg/liter AFM1 (after adjustment for sample weight). Changes in AFM1 content of milk powder samples were found statistically insignificant (P > 0.05 and P > 0.01) for 3- and 6-month storage periods.     

Aflatoxin B1 and its interconverting metabolite aflatoxicol in milk: the situation in Mexico.

Between 1996 and 1998, 580 litres of milk in Mexico were surveyed for aflatoxin B(1) (AFB(1)) and its metabolite aflatoxicol (AFL), which are mutagenic and carcinogenic mycotoxins that interconvert AFB(1)-AFL-AFB(1). The seven most consumed brands from different regions of Mexico included pasteurized and ultrapasteurized milk with four different fat levels: whole fat (28-33 g l(-1)), half-skimmed (10-20 g l(-1)), light (1-4 g l(-1)) and with vegetable oil (33 g l(-1)). Aflatoxins in each sample were concentrated with total aflatoxin immunoaffinity columns and quantitated by high-performance liquid chromatography. A milk sample was considered contaminated if it contained >/=0.05 microg l(-1) AFL. Pasteurization and ultrapasteurization of milk did not control contamination with AFL, which was present in 13% of samples at >/=0.05 microg l(-1) and in 8% at >/=0.5 microg l(-1), with a range of AFL from 0 to 12.4 microg l(-1). AFB(1) was present mainly in traces (0-0.4 microg l(-1)). The safest milk in relation to AFL contamination was imported milk powder with vegetable oil. There was a significant correlation between contamination of milk with AFL and the autumn (p<0.0002); the fat content was not significant.     

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.     

Immunoaffinity clean-up and direct fluorescence measurement of aflatoxins B1 and M1 in pig liver: comparison with high-performance liquid chromatography determination.

An improved analytical method for aflatoxin B1 (AFB1) and aflatoxin M1 (AFM1) determination in pig liver is described, using an aqueous methanol extraction, an immunoaffinity column clean-up step and a direct fluorometric measurement for toxin detection and quantification. A detection limit of 1.0 microg kg-1 was achieved for AFB1 and AFM1. Mean recoveries of 80.7+/-9.0% for AFB1 spiked at 1.0-9.7 microg kg-1 levels and of 76.7+/-6.6% for AFM1 spiked at 1.0-5.5 microg kg-1 levels were obtained. Recovery data for spiked samples were statistically compared with those obtained by the same extract using classical reversed-phase high-performance liquid chromatography (RP-HPLC) with fluorescence detection, showing a significant correlation (p相似文献   

Maternal dietary habits and mycotoxin occurrence in human mature milk

During 2006, 82 samples of human mature milk were collected at Italian hospitals and checked for aflatoxin M1 (AFM1) and ochratoxin A (OTA) by immunoaffinity column extraction and HPLC. AFM1 was detected in four (5%) of milk samples (ranging from < 7 ng/L to 140 ng/L; mean level: 55.35 ng/L); OTA was detected in 61 (74%) of milk samples (ranging from < 5 ng/L to 405 ng/L; mean level: 30.43 ng/L. OTA levels were significantly higher (p less, not double equals 0.05) in milk of habitual consumers of bread, bakery products and cured pork meat. No other statistically significant differences were observed although habitual consumers of pasta (p = 0.059), cookies (p = 0.061) and juices (p = 0.063) had mean contamination values of OTA higher than the moderate consumer. The very few AFB1 positive samples did not allow statistical comparisons. The present study confirms that the occurrence of OTA in human milk is related to maternal dietary habits. The findings support the possibility of dietary recommendations to woman, during pregnancy and lactation, aimed to tentatively reduce the OTA contamination of human milk.     

Excretion pattern of aflatoxin M1 in milk of goats fed a single dose of aflatoxin B1

The feedstuffs used in dairy animals must be able to give consumers confidence about the wholesomeness of milk with regard to aflatoxin contamination. The aim of this study was to determine the excretion patterns of aflatoxin M(1) (AFM1) in the milk of dairy goats fed a single dose of pure aflatoxin B(1) (AFB1), which can occasionally occur if feeds are infected by hot-spot growth of molds that produce aflatoxins. Five dairy goats in midlactation were administered 0.8 mg of AFB1 orally. Individual milk samples were collected for 84 h after AFB1 dosage. Aflatoxin M(1) was found in milk in the highest concentration. In all goats, AFM1 was not detected in milk before AFB1 administration, but was detected in the first milking following AFB1 administration. The excretion pattern of AFM1 concentration in milk was very similar in all goats even if the values of the concentration differed between animals. The peak values for AFM1 concentration in milk was observed in milk collected during the milking at 3 and 6h. After the peak, the AFM1 in milk disappeared with a trend that fitted well a monoexponential decreasing function, and the toxin was not detected after 84 h. Only about 0.17% of the amount of AFB1 administered was detected as AFM1 in milk, and about 50% of this was excreted in the first liter of milk yielded after AFB1 intake. Correct procedures to prevent growth of molds, and consequent AFB1 contamination, on the feedstuffs for lactating goats represent the key to providing consumers a guarantee that milk is not contaminated by AFM1.     

Presence of aflatoxin M1 in pasteurized milk from Morocco

Fifty four samples of pasteurized milk produced by five different dairies from Morocco were surveyed for the presence of aflatoxin M1 (AFM1) using immunoaffinity columns and liquid chromatography coupled to fluorescence detection. Confirmation of AFM1 identity in positive samples was based on the formation of AFM1 hemi-acetal derivative (AFM2a) after derivatization with trifluoracetic acid. Analytical results showed that 88.8% of the samples were contaminated with AFM1; 7.4% being above the maximum level of 0.05 microg/L set by the Moroccan and European regulations for AFM1 in liquid milk. The incidence of AFM1 in milk from these dairies was 100, 92.3, 90, 83.3 and 77.7% respectively, with AFM1 levels ranging from 0.001 to 0.117 microg/L and a mean value of 0.0186 microg/L. Based on the results presented in this study, the estimated daily intake of AFM1 was 3.26 ng/person/day. In this work, data on the natural occurrence of AFM1 in pasteurized milk produced in Morocco is presented for the first time.     

Short communication: Aflatoxin M1 in dairy products sold in Şanlıurfa,Turkey

The aim of this study was to detect the presence of aflatoxin M₁ (AFM1) in samples of raw milk (n = 38), UHT milk (n = 12), white pickled cheese (n = 50), and yogurt (n = 50) collected from the ?anl?urfa city markets and locally produced dairy products by ELISA. The mean contamination rates were 56.74 ± 40.32, 43.1 ± 23.19, 103.2 ± 29.13, and 55.28 ± 12.68 ng/kg, respectively, for raw milk, UHT milk, white pickled cheese, and yogurt. According to the data, 21 (55%) raw milk, 3 (25%) UHT milk, 10 (20%) white pickled cheese, and 10 (20%) yogurt samples were contaminated with AFM1 over the acceptable levels (≥50 ng/kg), ranging from 0.82 to 130.89 ng/kg. None of the white pickled cheese samples contained AFM1 levels above the Turkish legal limit (250 ng/kg). Consequently, the AFM1 contamination levels determined in this study in white pickled cheese were not considered to pose a serious public health hazard. However, the AFM1 levels in raw and UHT milk and yogurt samples indicate an increased human health risk in Turkey related to high aflatoxin levels. Therefore, milk and dairy products have to be monitored by the Turkish public health authorities continuously to detect AFM1 contamination.     

Survey of aflatoxin M1 in cow's milk for human consumption in Kerman Province of Iran

The aim of this study was to assess levels of aflatoxin M₁ (AFM1) in milk samples from Kerman, Iran. AFM1 was detected in 72 samples, ranging in concentration from <0.01 to 0.41?µg?l^?1. The samples were analyzed using immunoaffinity column for clean-up and HPLC for determining AFM1. Milk samples were collected from six dairy farms. AFM1 was found in ～50% of the milk samples. The average level of AFM1 was below the tolerance limit (0.05?µg?l^?1), but 50% of the samples had greater levels than the maximum tolerance limit accepted by EU and the Iranian national standard. The method detection limit and limit of quantification were 0.01 and 0.03?µg?l^?1, respectively, and recovery of the method was 87%. The results showed that AFM1 contamination is a serious problem for public health. To achieve a low level of AFM1 in milk, cattle feed must be monitored regularly for aflatoxin contamination and protected from fungal contamination as much as possible.     

A novel method for elimination of aflatoxin M1 in milk using Lactobacillus rhamnosus GG biofilm

This study aimed to develop a new method for detoxification of milk from aflatoxin M1 (AFM1) by using Lactobacillus rhamnosus GG biofilm. After inoculation of milk contaminated with AFM1 into L. rhamnosus GG biofilm, the unbound AFM1 was extracted and quantified by HPLC. The stability of the formed AFM1/biofilm complex using different AFM1 contamination levels of milk was also studied. We found that the percentages of bound AFM1 by L. rhamnosus GG biofilm reached up to 60.74%. While no significant difference in milk proteins content was observed after AFM1 binding, some changes in total dry matter and fat content were noticed.     

Survey of the occurrence of aflatoxin M1 in dairy products marketed in Italy: second year of observation.

During 1996, 161 samples of milk, 92 samples of dry milk for infant formula and 120 samples of yoghurt, were randomly collected in supermarkets and drug stores in four big Italian cities, and checked for aflatoxin M1 (AFM1) by immunoaffinity column extraction and HPLC. AFM1 was detected in 125 (78%) of milk samples (ranging from < 1 ng/l to 23.5 ng/l; mean level: 6.28 ng/l), in 49 (53%) of dry milk samples (ranging from <1 ng/l to 79.6 ng/kg; mean level: 32.2 ng/kg) and in 73 (61%) of yoghurt samples (ranging from <1 ng/kg to 32.1 ng/kg; mean level: 9.06 ng/kg). Altogether, only four samples of dry milk were over the legal limits established by the EC in 1999. It is concluded that during 1996, despite the widespread occurrence of AFM1, mean contamination levels in dairy products sold in Italy were not a serious human health hazard.     

Occurrence of aflatoxin M1 in retail milk samples from Bogotá, Colombia.

A study was conducted to establish the occurrence and levels of contamination of aflatoxin M1 (AFM1) in retail milk from Bogotá, Colombia. A total of 241 samples were analysed during 2004 and 2005. Samples were cleaned up by an immunoaffinity column and AFM1 was quantified by liquid chromatography with fluorescence detection. A total of 69.2 and 79.4% of the samples analysed during 2004 and 2005, respectively, were found to contain levels of AFM1 above 10 ng l(-1). Levels of contamination ranged from 10.7 to 213.0 ng l(-1) in 2004, and from 10.6 to 288.9 ng l(-1) in 2005. Despite the high incidence of AFM1 found in the milk samples analysed, all samples complied with current local regulations, which allow AFM1 content in milk up to 400 ng l(-1). However, due to the high incidence of AFM1 in milk found in the present study, it is recommended that a permanent surveillance programme be established for milk consumed in Bogotá in order to prevent milk lots containing levels above the regulatory level entering the food chain.     

Aflatoxin M1 in yoghurts in Portugal

Aflatoxin M1 (AFM1) may occur in milk and milk products, resulting from the ingestion of aflatoxin B1 in feedstuffs by dairy cow. Ninety-six samples of commercial yoghurts (48 natural yoghurts and 48 yoghurt with pieces of strawberries) that are produced in Portugal were analyzed for the presence of AFM1 by immunoaffinity column extraction and high-performance liquid chromatography (HPLC). The limit of detection was 10 ng/kg. The recoveries of AFM1 from the samples spiked at levels of 10.0, 50.0, 100.0 and 150.0 ng/kg were 88.0%, 91.0%, 93.0% and 99.0%, respectively. AFM1 was detected in 18 (18.8%) of yogurt samples ranging from 19 to 98 ng/kg, and 78 samples (81.2%) did not reveal the presence of the toxin. Of the 48 natural yoghurts tested, only two (4.2%) were contaminated with 43 and 45 ng/kg of AFM1. Of the 48 yoghurts with pieces of strawberries tested, 16 samples (33.3%) contained levels ranging from 19 to 98 ng/kg; six samples (12.5%) were contaminated with low levels ranging from 19 to 35 ng/kg; four samples (8.3%) were contaminated with levels ranging from 36 to 50 ng/kg, two samples (4.2%) with levels of 51 and 65 ng/kg and four samples (8.3%) presented high contamination levels, from 90 to 98 ng/kg. This paper reports the data of the first survey on the presence of AFM1 in yoghurt in Portugal.     

Potential public health risk due to consumption of contaminated bovine milk with aflatoxin M1 and Coxiella burnetii in the West of Iran

This study aimed to evaluate the probable public health hazard imposed by bovine milk in relation to aflatoxin M1 (AFM1) and Coxiella burnetii in the West of Iran. The assessment of AFM1, using an ELISA test, indicated 62.22% and 21.11% of 45 samples of raw and pasteurised milk were above the permissible content of Codex and Iranian standard levels, respectively. Further, anti‐C. burnetii antibody was detected in 63.04% of bulk tank milk samples, with six samples harbouring the bacterial genome. High AFM1 contamination levels and an endemic pattern of Q fever warrant continuous surveillance programmes in the studied region.     

Aflatoxin M 1 contamination in commercial samples of milk and dairy products in Kuwait

As part of the programme on monitoring of environmental contaminants in food stuffs in Kuwait, 54 samples of fresh full cream and skimmed milk, powdered milk, yoghurt, and infant formula were analysed for aflatoxin M 1 (AFM 1 ) by HPLC following sample clean up using immuno-affinity columns. Of samples, 28% were contaminated with AFM 1 with 6% being above the maximum permissible limit of 0.2 μg l -1 . Three fresh cow milk samples collected from a private local producer showed the highest level of 0.21 μg l -1 AFM 1 . There was no contamination with AFM 1 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 AFM 1 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 any worsening in the situation that may depend on market changes or on unfavourable climatic developments.     

Aflatoxin B(1) contamination of parboiled rice samples collected from different states of India: A multi-centre study.

Under a multi-centre study conducted by the Indian Council of Medical Research, 1,511 samples of parboiled rice were collected from rural and urban areas of 11 states representing different geographical regions of India. These samples were analysed for contamination with aflatoxin B(1.) The presence of aflatoxin B(1) at levels=5 microg g(-1) was found in 38.5% of the total number of samples of the parboiled rice. About 17% of the total samples showed the presence of aflatoxin B(1) above the Indian regulatory limit of 30 microg kg(-1). No statistically significant difference in percentage of samples contaminated with >30 microg kg(-1) was observed between pooled rural (19.4%) and urban (14.5%) data. A median value of 15 microg kg(-1) of aflatoxin B(1) was observed in samples from Assam, Bihar and Tripura. In all other states surveyed the median value was <5 microg?kg(-1).     

Aflatoxin residues in eggs of laying Japanese quail after long-term administration of rations containing low levels of aflatoxin B1.

The aim was to evaluate the excretion of residues of aflatoxin B(1) (AFB(1)), aflatoxin M(1) (AFM(1)), aflatoxin B(2a) (AFB(2a)) and aflatoxicol (AFL) in eggs of laying Japanese quail fed rations with low levels of aflatoxin B(1) for 90 days. The quail were randomly assigned into four experimental groups and given prepared rations containing either 0 (controls), 25, 50 or 100 microg AFB(1) kg(-1) feed. Thirty-two eggs per treatment were collected on days 1-7, 10, 20, 30, 60 and 90 of the aflatoxin treatment period, and submitted to aflatoxin analysis by high-performance liquid chromatography. Average egg production and feed consumption were not affected ( p > 0.05) by AFB(1). Egg weight was significantly lower ( p<0.05) only for groups exposed to 100 microg AFB(1) kg(-1). Residues of aflatoxins were detected in eggs at levels that ranged from 0.01 to 0.08 microg kg(-1) (AFB(1)), 0.03-0.37 microg kg(-1) (AFM(1)), 0.01-1.03 microg kg(-1)(AFB(2a)) and 0.01-0.03 microg kg(-1) (AFL). Results indicate that the excretion of aflatoxin residues in quail eggs might occur at relatively low concentrations under conditions of long-term exposure of quail to low levels of AFB(1).     

Determination of aflatoxin B1 in food and feedstuffs in Cuba (1990 through 1996) using an immunoenzymatic reagent kit (Aflacen).

The presence of aflatoxin B1 was analyzed in imported food and feedstuffs of national production in the period of 1990 through 1996, destined to animal and human consumption using an immunoenzymatic reagent kit (Aflacen, Ckure, la Habana, Cuba) with a detection limit of 0.3 microg/kg. It was found that the 17.04% of a total of 4,594 analyzed samples presented aflatoxin B1, and the biggest percentages were in sorghum and peanut with an 83.3 and 40.4%, respectively. The corn, oat, wheat, and soy are fundamental raw ingredients in the elaboration of concentrates. Percentages of contamination with aflatoxin B1 of 23.3, 10.7, 25, and 4.6 were found in corn, oat, wheat, and soy, respectively. Other analyzed foods like rice, beans, and peas presented percentages of contamination with aflatoxin B1 inferior to 5% of the analyzed samples. It was found that more than 455 samples surpassed the value of 10 microg/kg. Corn and peanut products present a high demand in population showing levels of contamination superior to 50 microg/kg. The 11.3% of the samples contaminated with aflatoxin B1 have values between 1 and 20 microg/kg, where peanut and concentrates show the highest percentages (21.9 and 18.7), respectively. These results show levels of aflatoxin B1 in the population that constitute a great risk for human and animal health.     

Occurrence of aflatoxin M1 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 M₁ (AFM₁) 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.     

Proficiency testing for the evaluation of the ability of European Union-National Reference laboratories to determine aflatoxin M1 in milk at levels corresponding to the new European Union legislation

In 1992, the European Union set up a network of National Reference Laboratories and charged the Community Reference Laboratory with the responsibility to design a proficiency testing scheme for assessing the analytical ability of laboratories involved in the official control of aflatoxin M1 in milk. Since 1996, two exercises of proficiency testing have been performed on samples of milk powder and liquid milk at various levels of aflatoxin M1 contents. The trials were conducted according to ISO Guide 43, in particular for the homogeneity testing of sample batches and for the calculation of laboratory z-scores. The National Reference Laboratories officially designated by their governments participated in this programme. Samples were naturally-contaminated milk obtained by feeding cows with aflatoxin B1-contaminated feed. The levels of aflatoxin M1 in the samples ranged from 0.2 to 0.7 microg/kg in milk powder and from 0.05 to 0.07 microg/l in liquid milk. These levels were chosen as being close to the European Union-regulated limit of 0.05 microg of aflatoxin M1 per litre. The results produced by laboratories were compiled and statistically analysed to detect any outlying results and to calculate the individual z-scores. Except for one laboratory in each exercise, all laboratories exhibited acceptable or questionable z-scores. The interlaboratory relative standard deviation for reproducibility (RSDR) obtained for both 1996 and 1998 exercises were in the range 15.7-30.3%. Compared with other published studies, this indicates a very good precision for the performance of this laboratory network in the analysis of traces of aflatoxin M1 in milk.