Aflatoxin Contamination of Milk Marketed in Pakistan: A Longitudinal Study

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.

Assessment of aflatoxin M1 exposure and associated determinants in children from Lahore, Pakistan

Aflatoxins are potent carcinogenic and immunomodulatory mycotoxins, and exposure may lead to deleterious effects on human health. This study aimed to detect aflatoxin M₁ (AFM₁) as biomarker of exposure and determine associated risk factors in children attending a specialized-childcare hospital in Lahore. Urine samples collected from 238 children (1-11 years) during winter (January-mid-March 2020) and hot-humid summer (August-September 2020) were tested for AFM₁ presence using ELISA. Data on potential risk factors were also collected. Of 238 samples, 156 (65.5%) were positive for urinary AFM₁. Season was significantly associated (OR = 2.64; 95% CI = 1.49-4.79; p = 0.001) with AFM₁ positivity; prevalence was higher in hot-humid months (74.6%) than winter (57.3%). The place of living was also significantly associated (OR = 2.21; 95% CI = 1.25-3.97; p = 0.007), and urinary AFM₁ positivity was higher in urban children (71.1%) compared to rural (58.3%). Median value for creatinine-adjusted AFM₁ was 1.9 ng/mg creatinine (Q1-Q3 = 0.82-6.0 ng/mg creatinine), while non-creatinine-adjusted AFM₁ was 0.57 ng/mL (Q1-Q3 = 0.23-1.4 ng/mL). Significantly higher urinary AFM₁ levels were detected in children; age ≤2 years (p = 0.037), who consumed more milk (p = 0.048), and who presented to the nutrition clinic (p = 0.003). These findings highlight the need for an effective control program to reduce the AFM₁ burden in children.

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.

Occurrence of Aflatoxin M1 in Milk and Dairy Products Traded in São Paulo, Brazil: An Update

The aim of this study was to conduct an up-to-date investigation on the occurrence levels of aflatoxin M1 (AFM1) in samples of raw milk (n = 40), pasteurized milk (n = 44), ultra-high temperature (UHT) milk (n = 27), Minas cheese (n = 57), and yogurt (n = 44) traded in São Paulo state, Brazil. AFM1 was extracted from fluid milks and dairy products using immunoaffinity columns and determined by high performance liquid chromatography. AFM1 was detected at the mean level of 0.080 ± 0.071 µg/L or kg in 72 samples (34.0%) evaluated in the study (n = 212). Detectable levels of AFM1 were observed in five samples of raw milk (12.5%), 16 samples of pasteurized milk (36.4%), 13 samples of UHT milk (48.1%), 27 samples of cheese (47.4%), and 11 samples of yogurt (25.0%), although none of them had concentrations above the maximum permitted levels (MPL) for AFM1 adopted in Brazil. However, 11.7% (n = 13) of samples of raw, pasteurized, and UHT milks would have AFM1 concentrations above the MPL of 0.05 μg/L adopted in the EU. The maximum level was detected in one cheese sample containing 0.695 µg/kg. Although none of the samples exceeded the Brazilian MPL, the high frequencies of AFM1 in Brazilian milk products warrant concern about their contribution to the human exposure to aflatoxins. Because aflatoxins are among the most potent carcinogens known, the results of this trial stress the need for stringent measures in the milk production system to avoid AFM1 in milk and derived products.

Farmer’s knowledge and suggested approaches for controlling aflatoxin contamination of raw milk in Pakistan

Monitoring of aflatoxin levels in milk is often complicated in developing countries due to the dominance of informal markets channeling milk in raw form. Farmer’s awareness and voluntary participation in aflatoxin mitigation can be critical in such scenarios. Therefore, the present study was conducted to understand the perceptions of dairy farmers about aflatoxins and link it with aflatoxin mitigation programs on milk in Pakistan. Information was collected from 450 peri-urban dairy farmers in seven cities using questionnaires. Majority (77.9%) of the farmers were aware of the negative impact of moldy feed on animal health. However, only 40.6% of the farmers were aware of the transferability of the toxins from moldy feed to milk. The farmers had almost no awareness of aflatoxins as 95% never heard of the term. After receiving an onsite briefing on effects of the toxin on animal and human health, and its transferability to milk, 98.3% farmers showed willingness to buy aflatoxin-safe feedstuffs, while 88.5% showed willingness to control aflatoxin in milk. Around half of the farmers considered aflatoxin control programs as affordable. On average, farmers agreed to pay 10.1% higher price for aflatoxin certified oilseed cakes. Availability of feedstuffs certified of low aflatoxin content was suggested by 22% of the participants as the critical step in reducing aflatoxins in milk. Other important suggestions included; subsidy on quality feeds (18%), raising awareness (18%), and legislation and monitoring (16%). The present results suggest that the current practice of milk monitoring in the country can yield desirable results only if it is coupled with feed certification programs ensuing availability of aflatoxin-safe feeds. Further, awareness can positively impact participation of producers in aflatoxin control programs. In this regard, awareness about effects of aflatoxins on animal health was found to be a more powerful trigger of voluntary control compared with the awareness of the toxin’s transferability to milk.

Seasonal Occurrence of Aflatoxin M1 in Raw Milk during a Five-Year Period in Croatia: Dietary Exposure and Risk Assessment

This study’s objective was to estimate the seasonal occurrence of aflatoxin M₁ (AFM₁) in cow’s milk between winter 2016 and winter 2022 and to assess dietary exposure and risk assessment for the adult Croatian population. In total, 5817 cow milk samples were screened for AFM₁ concentrations using the enzyme immunoassay assay (ELISA). For confirmation purposes of AFM₁ concentration above the European Union maximum permitted level (MRL), ultra high-performance liquid chromatography with tandem mass spectrometry was performed. In 94.7% of milk samples, AFM₁ levels were below the detection limit (LOD) of the ELISA test. For 3.47% of samples, the AFM₁ was between the LOD and MRL values. Only 1.87% of all samples exceeded the MRL. The mean value of elevated AFM₁ in different seasons ranged between 59.2 ng/kg (autumn 2017) and 387.8 ng/kg (autumn 2021). The highest incidences of positive AFM₁ were determined in autumn and winter and the maximum (6.4%) was in winter 2019/2020. The largest percentage of positive samples (69.7%) was found in central Croatia. The estimated daily intakes for positive samples ranged between 0.17 and 2.82 ng/kg body weight/day. Risk assessment indicated a high level of concern during autumn and winter, especially for consumers of large amounts of milk.

Super-Sensitive LC-MS Analyses of Exposure Biomarkers for Multiple Mycotoxins in a Rural Pakistan Population

High levels of mycotoxin contamination have been reported in various food commodities in Pakistan, however, there has been no exposure assessment study using multiple mycotoxins’ biomarkers. This study aimed to simultaneously assess the exposure to the five major mycotoxins: aflatoxin B1 (AFB1), deoxynivalenol (DON), fumonisin B1 (FB1), ochratoxin A (OTA) and zearalenone (ZEN) in a Pakistani population using an integrated approach of human biomonitoring. Human urine samples (n = 292) were analyzed by a super-sensitive liquid-chromatography tandem mass spectrometry (LC-MS/MS) method. Rice and wheat were also collected and analyzed for mycotoxins by the LC-MS/MS method. Food consumption data were collected using a 24 h recall method. A high prevalence of urinary AFM1 (66%, mean ± SD 20.8 ± 41.3 pg/mL) and OTA (99%, 134.7 ± 312.0 pg/mL) were found, whilst urinary DON, FB1 and ZEN levels were low. The probable daily intake (PDI) derived from the urinary biomarkers revealed that 89% of the participants had exposure to OTA exceeding the established tolerable daily intake (TDI = 17 ng/kg bw/day). The average PDI of AFB1 for the studied population was 43 ng/kg bw/day, with rice as the main source of AFB1 exposure. In summary, exposure to AFB1 and OTA are of health concern and require further management.

The efficacy of clay bentonite, date pit, and chitosan nanoparticles in the detoxification of aflatoxin M1 and ochratoxin A from milk

Aflatoxin M₁ (AFM₁) and ochratoxin A (OTA) are highly toxic mycotoxin metabolites that are found as food pollutants, posing health risks to humans and animals. The objective of the current study is to establish a sensitive, reliable method for determining AFM₁ and OTA using high-performance liquid chromatography (HPLC) and attempting to assess the efficacy of bentonite, date pit, and chitosan nanoparticles for AFM₁ and OTA detoxification from contaminated milk. As revealed, AFM₁ was found in 65.7% of analyzed samples ranging from 4.5 to 502 ng/L, while 25.7% of examined samples contained OTA ranging from 1.45 to 301 ng/L. Furthermore, for AFM₁ and OTA. The advanced procedure was thoroughly validated by evaluating linearity (R² > 0.999), LOD (0.9615 and 0.654 ng/L), and LOQ (2.8846 and 1.963 ng/L), recovery (93-95% and 87-91%), as well as precision (≤ 1%RSD). The experimental data revealed a higher removal efficiency of bentonite and date pit than chitosan nanoparticles in the case of AFM₁ (68%, 56%, and 12%) and OTA (64%, 52%, and 10%), respectively with slight change in nutritional milk components like fat, protein, and lactose. Eventually, it is concluded that bentonite and date pit can be considered efficient adsorbing agents to extract AFM₁ and OTA from contaminated milk.

Occurrence and Health Risk Assessment of Aflatoxins through Intake of Eastern Herbal Medicines Collected from Four Districts of Southern Punjab-Pakistan

Eastern herbal medicines (HMs) are plant-derived naturally occurring substances with minimum or no industrial processing that have long been used in traditional medicine. Aflatoxins are frequent contaminants of plants. Therefore, these mycotoxins are likely to contaminate HMs and pose a health risk to individuals using them on a regular basis as preventive or curative treatments of various diseases. The present study aimed to determine aflatoxin levels in the most popular Pakistani HM formulations and to assess the health risk associated with the intake of aflatoxins. A total of 400 samples of HM formulations collected from four districts of Punjab were analyzed for the quantification of aflatoxins, out of which 52.5% were found to be contaminated. The average daily dose (ADD) of AFB1 and AFs through the intake of HM formulations ranged between 0.00483 and 0.118 ng/kg bw/day and between 0.00579 and 1.714 ng/kg bw/day, respectively. The margin of exposure (MOE) and population cancer risk ranged from 99.49 to 29378.8 and from 0.00011 to 0.0325 liver cancer cases/105 individuals/year (0.0075-2.455 liver cancer cases/105 individuals/75 years), respectively. Despite the low exposure to aflatoxins from HM formulations in the four studied Punjab (Pakistan) districts, the frequent contamination of the analyzed samples suggests that official measures should be considered to manage the associated risk.

Prevalence of contamination of aflatoxin M1 in milk: a retrospective analysis of studies conducted in Pakistan

Aflatoxins, produced by multiple fungal species, are present in several kinds of food items and animal feed. Several studies conducted in Pakistan have reported the presence of aflatoxin M₁ (AFM₁) in milk. Hence, owing to the public health concern and absence of general statistics regarding the prevalence of AFM₁ contamination, current study was aimed to investigate the prevalence of AFM₁ in milk in Pakistan. For this study, various databases were searched from 2007 to 2020. A random effect model was applied for analytical purpose and heterogeneity of selected studies was investigated with an I² index. Comprehensive meta-analysis (version 3) was used for analysis of data. According to the results, prevalence of AFM₁ in milk was 84.4% (95% CI 75.0-90.7%). Regarding the heterogeneity based on meta-regression, it has been observed that there was a significant difference between the effect of year of study and sample size with prevalence of AFM₁ in animal milk. These results suggest that AFM₁ contamination in animal milk is high in Pakistan. Hence, continuous monitoring of AFM₁ in animal milk requires utmost attention from the respective food and drug regulatory authorities of Pakistan so that the strict actions and preventive measures should be taken to prevent the prevalence of exposure of AFM₁ in animal milk.

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.

Determination of Aflatoxin M1 in Raw Milk from Different Provinces of Ecuador

Aflatoxin M1 (AFM1) is a mycotoxin from Aspergillus flavus and A. parasiticus, classified as carcinogenic and hepatotoxic. The objective of the present investigation was to determine its presence in raw milk from north-central Ecuador, constituted by the provinces of Pichincha, Manabí, and Santo Domingo de los Tsáchilas. These areas represent approximately 30% of Ecuadorian milk production. By the end of the investigation, a total of 209 raw milk samples were collected, obtained both during the dry (June and August) and rainy seasons (April and November) of 2019. AFM1 concentrations were measured with lateral flow immunochromatographic assays, and 100% of the samples were positive for this mycotoxin, presenting a mean value of 0.0774 μg/kg with a range of 0.023 to 0.751 μg/kg. These AFM1 levels exceeded the European Union regulatory limit of 0.05 μg/kg in 59.3% (124/209) of samples, while only 1.9% (4/209) exceeded the Ecuadorian legal limit of 0.5 μg/kg. By using non-parametric tests, significant differences were determined (p ≤ 0.05) between the provinces for months of study, climatic season (being higher in the dry season), and climatic region (greater in the coast region). On the other hand, there were no significant differences (p ≥ 0.05) between the types of producers or between production systems. Therefore, AFM1 contamination in raw milk does not present a serious public health problem in Ecuador, but a monitoring and surveillance program for this mycotoxin in milk should be developed to prevent consumer health problems.

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.

Aflatoxins in cotton seeds and cotton seed cake from Pakistan

A study was conducted to evaluate the natural occurrence of aflatoxins (AFB1, AFB2, AFG1, AFG2) in cotton seeds (n = 110) and cotton seed cake (CSC; n = 110) from Pakistan. All samples were screened by Enzyme-Linked ImmunoSorbent Assay (ELISA). Positive samples were further quantified by IAC-HPLC-FLD. Total contamination frequency and aflatoxins mean levels were 80% and 69 μg/kg in cotton seeds and the corresponding values for cotton seed cake 88% and 89 μg/kg, respectively. Aflatoxin B1was found in all positive samples and co-occurred with AFB2, AFG1, and AFG2. Sixty-four cotton seeds and 71 CSC samples contained aflatoxins levels higher than the ML set for animal feed (20 µg/kg). The results of the present study will help the regulatory authorities to formulate strategies for monitoring aflatoxins in animal feeds.

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.