Aflatoxin M1 in milk from urban and rural farmhouses of Punjab, Pakistan

Aflatoxins posing threat to food safety and security in Pakistan: Call for a one health approach

Aflatoxins are among the most important mycotoxins due to their widespread occurrence and adverse impacts on humans and animals. These toxins and/or their metabolites cannot be destroyed with cooking or boiling methods. Therefore, consumption of aflatoxin-contaminated food may lead to impaired growth, compromised immunity, stomach and liver cancer, and acute toxicity. These adverse effects along with food wastage might have detrimental consequences on a country's economy. Several studies from Pakistan reported a high prevalence of aflatoxins in food and feed commodities (Range; milk = 0.6-99.4%, cereals, and grains = 0.38-41%, animal feed = 31-100%). Notably, Pakistan reported very high figures of impaired child growth-stunted 40.2%, wasted 17.7% and underweight 28.9%-that could be associated with the higher aflatoxin prevalence in food items. Importantly, high aflatoxins prevalence, i.e. 100%, 69% and 60.5%, in children has been reported in Pakistan. Food and feed are more prone to aflatoxin contamination due to Pakistan's hot and humid climate; however, limited awareness, inadequate policy framework, and weak implementation mechanisms are the major obstacles to effective control. This review will discuss aflatoxins prevalence, associated risk factors, adverse health effects, required regulatory regime, and effective control strategies adopting the One Health approach to ensure food safety and security.

Comprehensive Review of Aflatoxin Contamination, Impact on Health and Food Security, and Management Strategies in Pakistan

Aflatoxins (AFs) are the most important toxic, mutagenic, and carcinogenic fungal toxins that routinely contaminate food and feed. While more than 20 AFs have been identified to date, aflatoxin B1 (AFB1), B2 (AFB2), G1 (AFG1), G2 (AFG2), and M1 (AFM1) are the most common. Over 25 species of Aspergillus have been shown to produce AFs, with Aspergillus flavus, Aspergillus parasiticus, and Aspergillus nomius being the most important and well-known AF-producing fungi. These ubiquitous molds can propagate on agricultural commodities to produce AFs in fields and during harvesting, processing, transportation, and storage. Countries with warmer climates and that produce foods susceptible to AF contamination shoulder a substantial portion of the global AF burden. Pakistan's warm climate promotes the growth of toxigenic fungi, resulting in frequent AF contamination of human foods and animal feeds. The potential for contamination in Pakistan is exacerbated by improper storage conditions and a lack of regulatory limits and enforcement mechanisms. High levels of AFs in common commodities produced in Pakistan are a major food safety problem, posing serious health risks to the population. Furthermore, aflatoxin contamination contributes to economic losses by limiting exports of these commodities. In this review, recent information regarding the fungal producers of AFs, prevalence of AF contamination of foods and feed, current regulations, and AF prevention and removal strategies are summarized, with a major focus on Pakistan.

Incidence of Aflatoxin M1 in Milk and Milk Products from Punjab, Pakistan, and Estimation of Dietary Intake

In the present study, 124 samples of milk and milk products were analyzed for the presence of aflatoxin M1 (AFM1), which were purchased from the central cities of Punjab, Pakistan. The analysis was carried out using reverse-phase liquid chromatography, which was equipped with a fluorescence detector. The results showed that 66 samples (53.8%) of raw milk and milk products were found to be contaminated with detectable levels of AFM1 above ≤50 ng/L, and 24.2% of the samples had levels of AFM1 higher than the permissible limit of the European Union (EU; 50 ng/kg). In total, 53.6% of the raw milk, 57.8% of the UHT (ultra-heat-temperature) milk, 45% of the powdered milk, 57.1% of the yogurt, 55.5% of the cheese, and 50% of the buttermilk samples had levels higher than the LOD, i.e., 4 ng/L. The highest mean of 82.4 ± 7.8 ng/kg of AFM1 was present in the positive samples of raw milk. The highest dietary intake of AFM1 was found in infants’ milk (5.35 ng/kg/day), UHT milk (1.80 ng/kg/day), powdered milk (5.25 ng/kg/day), and yogurt (1.11 ng/kg/day). However, no dietary intake was detected in the cheese and butter milk samples used for infants. The results from the undertaken work are beneficial for establishing rigorous limits for AFB1 in animal feed, especially considering the high prevalence rate of hepatitis cases in the central cities of Punjab, Pakistan.

Occurrence of Aflatoxins in Edible Vegetable Seeds and Oil Samples Available in Pakistani Retail Markets and Estimation of Dietary Intake in Consumers

Aflatoxins (AFs) are secondary metabolites toxic to humans as well as animals. The environmental conditions, conventional agricultural practices, and illiteracy are the main factors which favor the production of AFs in food and feed. In the current study 744 samples of vegetable seeds and oils (soybean, sunflower, canola, olive, corn, and mustard) were collected and tested for the presence of aflatoxin B₁ (AFB₁) and total AFs. Liquid-liquid extraction was employed for the extraction of AFs from seeds and oil samples. Reverse phase high performance liquid chromatography equipped with fluorescence detection was used for the analysis. The results have shown that 92 (56.7%) samples of imported and 108 (57.0%) samples of local edible seeds were observed to be contaminated with AFs. All samples of edible seeds have AFB₁ levels greater than the proposed limit set by the European Union (EU, 2 µg/kg) and 12 (7.40%) samples of imported seeds and 14 (7.40%) samples of local seeds were found in the range ≥ 50 µg/kg. About 78 (43.3%) samples of imported edible oil and 103 (48.3%) sample of local edible oil were observed to be positive for AFs. Furthermore, 16 (8.88%) and six (3.33%) samples of imported vegetable oil have levels of total AFs in a range (21–50 µg/kg) and greater than 50 µg/kg, respectively. The findings indicate significant differences in AFs levels between imported and local vegetable oil samples (t = 22.27 and p = 0.009) at α = 0.05 and a significant difference in AFs levels were found between vegetable seeds and oil samples (t = −17.75, p = 0.009) at α = 0.05. The highest dietary intake was found for a local sunflower oil sample (0.90 µg/kg/day) in female individuals (16–22 age group). The results have shown considerably high levels of AFB1 and total AFs in seeds and oil samples and emphasise the need to monitor carefully the levels of these toxic substances in food and feed on regular basis.

The Presence of Aflatoxin M1 in Milk and Milk Products in Bangladesh

As milk provides both micro- and macronutrients, it is an important component in the diet. However, the presence of aflatoxin B₁ (AFB₁) in the feed of dairy cattle results in contamination of milk and dairy products with aflatoxin M₁ (AFM₁), a toxic metabolite of the carcinogenic mycotoxin. With the aim to determine AFM₁ concentrations in milk and milk products consumed in Bangladesh, in total, 145 samples were collected in four divisional regions (Sylhet, Dhaka, Chittagong, and Rajshahi). The samples comprised these categories: raw milk (n = 105), pasteurized milk (n = 15), ultra-high temperature (UHT)-treated milk (n = 15), fermented milk products such as yogurt (n = 5), and milk powder (n = 5). AFM₁ levels in these samples were determined through competitive enzyme-linked immunosorbent assay (ELISA). Overall, AFM₁ was present in 78.6% of milk and milk products in the range of 5.0 to 198.7 ng/L. AFM₁ was detected in 71.4% of raw milk (mean 41.1, range 5.0–198.7 ng/L), and in all pasteurized milk (mean 106, range 17.2–187.7 ng/L) and UHT milk (mean 73, range 12.2–146.9 ng/L) samples. Lower AFM₁ levels were found in yogurt (mean 16.9, range 8.3–41.1 ng/L) and milk powder samples (mean 6.6, range 5.9–7.0 ng/L). About one-third of the raw, pasteurized, and UHT milk samples exceeded the EU regulatory limit (50 ng/L) for AFM₁ in milk, while AFM₁ levels in yogurt and milk powder samples were well below this limit. Regarding regions, lower AFM₁ contamination was observed in Chittagong (mean 6.6, max 10.6 ng/L), compared to Sylhet (mean 53.7, max 198.7 ng/L), Dhaka (mean 37.8, max 97.2 ng/L), and Rajshahi (mean 34.8, max 131.4 ng/L). Yet, no significant difference was observed in AFM₁ levels between summer and winter season. In conclusion, the observed frequency and levels of aflatoxin contamination raise concern and must encourage further monitoring of AFM₁ in milk and milk products in Bangladesh.

An overview of aflatoxin B1 biotransformation and aflatoxin M1 secretion in lactating dairy cows

Milk is considered a perfect natural food for humans and animals. However, aflatoxin B1 (AFB1) contaminating the feeds fed to lactating dairy cows can introduce aflatoxin M1 (AFM1), the main toxic metabolite of aflatoxins into the milk, consequently posing a risk to human health. As a result of AFM1 monitoring in raw milk worldwide, it is evident that high AFM1 concentrations exist in raw milk in many countries. Thus, the incidence of AFM1 in milk from dairy cows should not be underestimated. To further optimize the intervention strategies, it is necessary to better understand the metabolism of AFB1 and its biotransformation into AFM1 and the specific secretion pathways in lactating dairy cows. The metabolism of AFB1 and its biotransformation into AFM1 in lactating dairy cows are drawn in this review. Furthermore, recent data provide evidence that in the mammary tissue of lactating dairy cows, aflatoxins significantly increase the activity of a protein, ATP-binding cassette super-family G member 2 (ABCG2), an efflux transporter known to facilitate the excretion of various xenobiotics and veterinary drugs into milk. Further research should focus on identifying and understanding the factors that affect the expression of ABCG2 in the mammary gland of cows.

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 Contamination of Milk Produced in Peri-urban Farms of Pakistan: Prevalence and Contributory Factors

Aflatoxin M1 contamination of milk in Pakistan, like many developing countries, is poorly understood. The present study was therefore conducted to determine AFM1 contamination of milk and its contributory factors in Pakistan. We sampled milk and feedstuffs from 450 peri-urban dairy farms in seven major cities following a cross-sectional study design. Analysis of milk using ELISA revealed high contamination with an overall average of 3164.5 ng of AFM1/L, and significant differences (p < 0.001) between cities. The milk sampled from Gilgit, in northern hilly areas, had an average AFM1 level of 92.5 ng/L. Milk from other cities had 3529.7 ng/L average contamination, with only 5.7% samples qualifying the maximum tolerable limit of 500 ng of AFM1/L. Heavy mean aflatoxin contamination was found in bakery waste (724.6 μg/kg), and cottonseed cake (600.8 μg/kg). Rest of the other feedstuffs had moderate to low mean aflatoxin contamination, ranging from 66.0 μg/kg in maize stover to 3.4 μg/kg in wheat bran. The mean aflatoxin level in commercial dairy concentrates was 32.7 µg/kg. About 80% of the total aflatoxin intake of dairy animals was contributed by cottonseed cake alone due to its high aflatoxin contamination and proportion in dairy rations. On-farm storage time of oilseed cakes varied (p < 0.01) in different cities but was not associated with aflatoxin contamination. The exceptionally high AFM1 contamination suggests that milk from peri-urban dairy farms is a serious public health threat in Pakistan. This situation can be mitigated by reducing aflatoxin contamination in cottonseed cake and promoting the use of commercial concentrates and other feedstuffs with low contamination.

Occurrence of Aflatoxin M1 in Milk-based Mithae samples from Pakistan

Milk products with aflatoxin M1 (AFM1) contamination are a lethal dilemma worldwide due to their carcinogenic and mutagenic effects especially in developing countries. This study investigated the occurrence of AFM1 in milk-based mithae samples marketed in Lahore, Pakistan. Two hundred (n = 200) different types of mithae samples were analyzed for AFM1 using a HPLC florescence detector. Results showed that AFM1 was present in 76% of the analyzed samples, of which more than 80% had a much higher level of AFM1 than the European Union permissible level of i.e.0.05 μg/kg in milk products. The aflatoxin M1 in all the tested samples was observed in the range of 0.004 to 1.49 μg/kg. On average, the Gulab Jamun and Malai Laddu showed the highest level of aflatoxin M1 i.e. 1.49 and 1.17μg/kg, respectively. The lowest amount of aflatoxin M1 was found in Kalakand samples 0.004μg/ kg. The conclusion drawn from this data revealed that almost three-fourths of the mithae samples were highly contaminated with AFM1 due to their main component, milk. The consumption of milk-based mithae is popular due to health benefits as well as being part of tradition. Instead of being nourishing and beneficial, it is been found to be hazardous to human health due to aflatoxin contamination. Continued monitoring of aflatoxin M1with strict rules and regulations is required to prevent aflatoxin accumulation in this favorite food commodity.

Occurrence and Seasonal Variations of Aflatoxin M1 in Milk from Punjab, Pakistan

The manifestation of aflatoxins in feed and food is a major issue in the world as its presence leads to some health problems. This study investigates the incidence of aflatoxin M₁ (AFM₁) contamination in raw milk samples which were collected from Punjab, Pakistan. The Cluster Random Sampling technique was used to collect 960 milk samples from five different regions, and samples were collected every month. The AFM₁ level in raw milk was analyzed by the ELISA technique. The findings demonstrate that 70% of samples exceeded the United States permissible maximum residue limits (MRL 0.50 µg/L), with an overall AFM₁ level that ranged from 0.3 to 1.0 µg/L. AFM₁ contamination varied with the season: The highest average contamination was detected in winter (0.875 µg/L), followed by autumn (0.751 µg/L), spring (0.654 µg/L), and summer (0.455 µg/L). The Eastern region exhibited the highest average AFM₁ contamination (0.705 µg/L). Milk samples from the Northern region were found to be widely contaminated, as 86.9% samples exceeded the US MRL, followed by the Eastern region, with 72.3% samples being contaminated with >0.5 µg/L AFM₁. The study indicated that the raw milk supply chain was heavily contaminated. Recommendations and remedial measures need to be developed by regulatory authorities to improve the raw milk quality.

Aflatoxin Contamination of Milk Marketed in Pakistan: A Longitudinal Study

A longitudinal one-year study was conducted to determine aflatoxin M₁ levels in different types of milk marketed in Pakistan. Processed and raw liquid milk from 21 sources, two milk powder and six tea whitener brands were sampled on monthly basis from Islamabad. The aflatoxin M₁ levels in liquid milk were lower (p < 0.05) in summer (April to July) compared with the levels in winter (January, November and December). The mean aflatoxin M₁ levels were 254.9, 939.5, and 1535.0 ng/L in UHT, pasteurized, and raw milk, respectively (differing at p < 0.001). The mean toxin level in powdered milk after reconstitution was 522.1 ng/L. Overall, 12.9, 41.0, 91.9 and 50.0% of the UHT, pasteurized, raw and powdered milk samples, respectively, exceeded the Codex maximum tolerable limit of 500 ng of aflatoxin M₁/L. It was estimated that consumers of raw and processed milk were exposed to 11.9 and 4.5 ng aflatoxin M₁, respectively, per kg of body weight daily. The study indicates potential aflatoxin M₁ exposure risks for the consumers of raw milk in the country. The levels of the toxin though comparatively lower in milk powder, requires attention as this type of milk is consumed by infants.

Lactoferrin inhibits aflatoxin B1- and aflatoxin M1-induced cytotoxicity and DNA damage in Caco-2, HEK, Hep-G2, and SK-N-SH cells

Aflatoxins, including aflatoxin B₁ (AFB₁) and M₁ (AFM₁), are natural potent carcinogens produced by Aspergillus spp. These compounds, which can often be detected in dairy foods, can cause diseases in human beings. However, the molecular mechanisms involved in cytotoxicity, as well as methods for intervention, remain largely unexplored. For example, it is unclear whether lactoferrin (LF), a major antioxidant in milk, can inhibit the cytotoxicity of AFB₁ and AFM₁. In this study, we assessed AFB₁- and AFM₁-induced cell toxicity by measuring cell viability, membrane permeability, and genotoxicity, and then investigated the ability of LF to protect cells against AFB₁ and AFM₁. In Caco-2, HEK, Hep-G2, and SK-N-SH cells, 4 μg/mL AFB₁ or AFM₁ significantly inhibited cell growth, increased the level of lactate dehydrogenase, induced genetic damage, and increased the levels of signal-regulated kinase (ERK1/2) and c-Jun N-terminal kinase (JNK) (p < 0.05). AFB₁ was more genotoxic than AFM₁ in all four cell lines, especially in Hep-G2. In Caco-2, Hep-G2, and SK-N-SH, incubation of AF-treated cells with 1000 μg/mL LF significantly decreased cytotoxicity, oxidation level, DNA damage, and levels of ERK1/2 and JNK (p < 0.05). Our data demonstrate that AFB₁ or AFM₁ induced cytotoxicity and DNA damage in these four cell lines, and that LF alleviated toxicity by decreasing oxidative stress mediated by mitogen-activated protein kinase pathways.

Engaging One Health for Non-Communicable Diseases in Africa: Perspective for Mycotoxins

The role of mycotoxins-e.g., aflatoxins, ochratoxins, trichothecenes, zearalenone, fumonisins, tremorgenic toxins, and ergot alkaloids-has been recognized in the etiology of a number of diseases. In many African countries, the public health impact of chronic (indoor) and/or repeated (dietary) mycotoxin exposure is largely ignored hitherto, with impact on human health, food security, and export of African agricultural food products. Notwithstanding, African scientific research reached milestones that, when linked to findings gained by the international scientific community, make the design and implementation of science-driven governance schemes feasible. Starting from Nigeria as leading African Country, this article (i) overviews available data on mycotoxins exposure in Africa; (ii) discusses new food safety issues, such as the environment-feed-food chain and toxic exposures of food producing animals in risk assessment and management; (iii) identifies milestones for mycotoxins risk management already reached in West Africa; and (iv) points out preliminary operationalization aspects for shielding communities from direct (on health) and indirect (on trade, economies, and livelihoods) effects of mycotoxins. An African science-driven engaging of scientific knowledge by development actors is expected therefore. In particular, One health/One prevention is suggested, as it proved to be a strategic and sustainable development framework.

The aflatoxin M1 crisis in the Serbian dairy sector: the year after

During the last 3 years, high aflatoxin M1 (AFM1) concentrations in milk and dairy products occurred in Serbia. It resulted in periodical change of the official regulations regarding maximum levels (MLs) of AFM1 as set by the Serbian Government. The aim of this study was to compare the occurrence of AFM1 in raw milk and dairy products during 2015 and also to determine whether there were some differences in AFM1 level among seasons. The AFM1 level exceeded the European Union ML in 29.3% of raw milk and 4.2% of milk product samples. The highest level of AFM1 in raw milk was found during the autumn season, while during the rest of the 2015, it was significantly lower. Although the improvement of dairy products safety was evident in 2015 when compared to 2013 and 2014, the cause of high concentrations in raw milk remained unresolved yet. This study indicates that dairy plants introduced control measures and refused reception of too high contaminated raw milk.

Natural Occurrence of Mycotoxins in Food and Feed: Pakistan Perspective

Fungi are commonly present in the environment and can grow under favorable conditions on an extensive variety of substrates. During harvesting, handling, storage, and distribution, agricultural commodities are subjected to infection by toxigenic molds, which may cause spoilage and produce toxic metabolites called mycotoxins. Fungal contamination of various food commodities with consequent exposure of the community to mycotoxins is a hazard that may exist depending on environmental factors, crop health, and soil conditions. Mycotoxins represent serious consequences due to substantial economic loss and risk to health. The environmental conditions of Pakistan with its mostly warm temperature are conducive to growth of toxigenic fungi resulting in mycotoxin production in different food items. Moreover, the poor conditions of storage and deficiency in regulatory measures in food quality control worsen the situation in the country. This review encompasses mycotoxin contamination of food and feed in Pakistan. High concentrations of mycotoxins are found in some commodities that are used on a daily basis in Pakistan, which may be a concern depending on dietary variety and health conditions of individuals in the population. Therefore, the mycotoxin contamination of foodstuff with exceeding levels represents a serious health hazard for the local population. There is a need to conduct more studies to analyze mycotoxin occurrence in all types of food commodities throughout the country. For consumer safety and the country's economy, the regulatory authorities should take into account this issue of contamination, and control strategies should be implemented and the quality control system of food improved.