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Evaluation Of Aflatoxin M1 Contamination In Consuming Milk

Reyhaneh Rouhi1, Akbar Kazemi

2, Abdolreza Sotoodeh Jahromi

2*, Hassan Zabrtian

1, Alireza

Yousefi1, Abdolhossien Madani

3, Mohammad Hojjat-Farsangi

4

1.Research center for social determinants of health, Jahrom University of Medical Sciences,

Jahrom, Iran

2.Zonoses Research Center, Jahrom University of Medical Sciences, Jahrom, Iran

3.Research Center for Social Determinants in Health Promotion, Hormozgan University of

Medical Science, Bandarabbas, Iran

4.Department of Oncology-Pathology, Immune and Gene therapy Lab, Cancer Center

Karolinska (CCK), Karolinska University Hospital Solna and Karolinska Institute,

Stockholm, Sweden.

*Corresponding Author: Abdolreza Sotoodeh Jahromi, Zonoses Research Center, Jahrom

University of Medical Sciences, Jahrom, Iran

Abstract: Aflatoxin M1 (AFM1) has been categorized as a class 2B carcinogen and its

carcinogenicity was estimated to be one-tenth of that of AFB1. As milk is a major nutrient for

infants، children، convalescents and old people, the presence of AFM1 in commercial milk

and dairy products is a matter of concern. As milk is a major nutrient for infants، children،

convalescents and old people, the presence of AFM1 in commercial milk and dairy products

is a matter of concern. The aim of this survey was to determine concentrations of AFM1 in

raw and pasteurized milk marketed in Jahrom city located in southern of Iran during two

seasons. A total 120 milk samples including 90 raw milk samples and 30 pasteurized milk

samples were examined by ELISA method to determine AFM1 concentration in Jahrom (a

southern city in Iran), Jan. 2013 to jun. 2013. The presence of AFM1 was seen 8.33%

including 6.7% and 13.3% of raw pasteurized milk respectively. The results indicated that the

contamination of the kinds of milk in such level could be a serious public health problem.

Inspection of milk and dairy products is recommended for AFM1 contamination.

Key Words: Aflatoxin M1, Milk, Iran

INTRODUCTION

Mycotoxins, secondary metabolites of fungi, are toxic for humans and animals (1, 2), among

them, aflatoxins are produced by Aspergillus flavus and Aspergillus paratisicus and rarely by

Aspergillus nomius which contaminate plants and plant products particularly under

conditions that favor the growth of molds (1). The aflatoxin B1 (AFB1) has potent

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carcinogenic and mutagenic effects in humans (3), When cows that consume feed mixtures

containing corn polluted with AFB1 can then excrete aflatoxin M1 (AFM1) as ahydroxylated

metabolite of AFB1 in milk (1) and excreted as AFM1 in the urine and also in milk (4).

AFM1 has been categorized by the International Agency for Research on Cancer as a class 2B

carcinogen and its carcinogenicity was estimated to be one-tenth of that of AFB1 by the Joint

Expert Committee on Contamination and Food Additives in 2001 (5).

As milk is a major nutrient for infants، children، convalescents and old people, the presence of

AFM1 in commercial milk and dairy products is a matter of concern (6). Therefore, CODEX

recommends the establishment of maximum residue limit for AFM1 of 0.5 mg/kg (7).

AFM1 is relatively stable throughout pasteurization, sterilization, preparation and storage of

various dairy products (8). Milk is not only consumed in liquid form but also used for the

preparation of infant formulas, yogurt and cheese.

Infants in Iran usually consume pasteurized and sterilized milk after breast weaning and up to

3 years of age as the main source of food, so the problem is most important in this age group

(6).

Therefore, it is important to determine AFM1 level in milk and dairy products in order to

inform consumers of its potential hazard. There is little information on the basic diet,

including milk and milk products as well as AFM1concentrations in milk, in some cities of

Iran (9).

The aim of this survey was to determine concentrations of AFM1 in raw and pasteurized milk

marketed in Jahrom city located in southern of Iran during two seasons.

MATERIALS AND METHODS

A total 120 milk samples including 90 raw milk samples and 30 pasteurized milk samples

were randomly collected from supermarkets in Jahrom (a southern city in Iran), Jan. 2013 to

jun. 2013. Of these, 90 samples were raw milk and 30 samples were pasteurized milk .All of

the samples were transported at 2–4 °C in the icebox to the laboratory. The milk samples were

centrifuged at 3500g for 10 min at 10 °C. The upper creamy layer was removed by Pasteur

pipette for testing. The quantitative analysis of AFM1 in samples was performed by

competitive ELISA using commercial AFM1 test kit (R-Bio pharm AG, Darmstadt,

Germany).

According to Iranian national standard and accentuated by European Union (EU) and codex

Alimentarious Commission, (European Commission (EC), the presence of AFM1 level more

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than 50 ng/l in milk, considered as positive and less than 50 ng/l considered as negative for

AFM1 (7).

The results were analyzed by one-way analysis of variance (ANOVA) and considered

statistically difference at 95% confidence levels.

RESULTS

The result of analyses of AFM1 level showed that 10 milk samples (8.33%) including 6

samples (6.7%) of raw milk and 4 samples (13.3%) of pasteurized milk were contaminated

with AFM1 with higher than the maximum tolerance level of AFM1 in liquid milk according

to Iranian national standard and accentuated by European Union (EU), codex Alimentarious

Commission (50 ng/l) and European Commission (EC), (7).

There was not found significant difference between the level of AFM1 in raw and pasteurized

milk samples (P>0.05) (Fig. 1).

AFM1 contamination in the milks was seen the winter and there was not seen this

contamination in spring season (p<0.05).

Fig. 1: AFM1 contamination percentage in milk samples

6.70%

13.30%

Raw milk Pasteurized milk

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DISCUSSION

The results of this study showed that 8.33% consuming milk in Jahrom as a city in southern of

Iran have AFM1 contamination higher than 50ng/l. In present study the level of AFM1 in raw

and pasteurized milk samples showed no significant difference (P>0.05).

There are few literature data on the occurrence of AFM1 levels in milk and milk products in

Iran (6, 9, 10, 11, 12).

In comparison with those found in other Iranian cities the contamination which has been

found in present study is lower than those found in Gorgan (76 ng/l) and Tehran (61 ng/l) but

is higher than those found in Hamedan (8 ng/l), Rasht (44 ng/l), Shiraz (52 ng/l) (9, 10, 11,

12).

Our results about the contamination of pasteurized milk with AFM1 and about raw milk are in

agreement Shiraz (southern city of Iran) 17.8% (12) and with the result of study in Urmia

(north-west city of Iran) 6.25% (10).

AFM1 levels in samples of milk produced in Argentina were found to be very low and in no

case did the levels exceed the recommended limits for milk products (0.05 μg/l) (13). The

incidence of AFM1 contamination in raw milk analyzed in Portugal was 80.6%, including:

54.8% contained 0.005-0.010 μg/l, 6.5% had 0.011-0.02 μg/l and 19.3% contained 0.021-

0.050 μg/l (14).

The AFM1 milk contamination in Ankara, Turkey, was reported 88.23%, of which 36% were

contaminated with concentrations less than 50 ng/l and 64% exceeded the legal level of

AFM1 in milk (15).

During 2005, out of 45 raw milk samples analyzed in Italy, only one sample was positive to

the ELISA test, but the confirmation test values (0.035 μg/l) were below the legal limit (16).

AFM1 contamination of milk is the result of cows feeding on material containing AFB1. The

concentration of this mycotoxin in animal feed stuffs is influenced by the type, the time and

method of harvesting and temperature and relative humidity of storage facilities, all of which

vary among different regions of Iran (9).

In present study, AFM1 concentrations in milk samples were significantly higher in the colder

seasons in agreement with the results of other authors. For example Tajkarimi reported that

AFM1 concentrations in milk samples in winter were significantly higher than summer

(P<0.05), 30% of samples in winter were >50 ng/l; however, in summer 16% of samples were

>50 ng/l (17), because milking animals are fed with compound feeds in winter that are prone

to AFB1 contamination (2). In order to achieve a low level of AFM1, it is essential to conduct

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training programs for producers about the toxicity potential of aflatoxins, reduce the

concentration of AFB1 in animal feed by good manufacturing and storage and integrating it

with Hazard Analysis and Critical Control Points (HACCP) based safety program and doing

regular monitoring of milk and milk products (18).

Concentrations of AFM1 in milk found in the present study are similar to those reported in

other countries, especially those in Asian and Africa, although higher than those in many

European countries (19).

CONCLUSION

The results indicated that the contamination of the kinds of milk in such level could be a

serious public health problem. AFM1 concentration of milk and its products is potentially a

serious public health problem for all age groups. For this reason, milk and dairy products

should be inspected and controlled continuously for AFM1 contamination. Where

concentrations are unacceptably high, careful investigation of feed stuffs for contamination by

AFB1 are recommended.

ACKNOWLEDGMENT

Hereby, the authors acknowledge the authorities of Jahrom University of Medical Sciences

for financial support. Also authors thank all participants for their enrollment in this study.

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