Contamination profile of aflatoxin M1 residues in milk supply chain of Sindh, 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.

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.

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.

Monitoring of Aflatoxin M1 in milk using a novel electrochemicalaptasensorbased on reduced graphene oxide and gold nanoparticles

Accurate and rapid detection of Aflatoxins as one of the most hazardous compounds in foodstuffs is very important. In this study, a label-free electrochemical aptasensor was developed to identify aflatoxin M1 using a reduced graphene oxide (rGO) and gold nanoparticles (AuNPs)-based pencil graphite electrode (PGE). The morphological characteristics of the electrode surface were investigated using SEM and rGO functional groups were confirmed by FTIR. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques were used to characterize various stages of electrode modification. In order to optimize the impedimetric response of the aptasensor, aptamer immobilization time, aptamer concentration, and binding aflatoxin M1 with aptamer time were optimized. Under optimal conditions, the linear concentration range of 0.5-800 ng/L and limit of detection (LOD) of 0.3 ng/L were obtained for aflatoxin M1 by measuring the resistance charge transfer data. Finally, the fabricated aptasensor was successfully used to measure AFM1 compared to HPLC method.

Detection of aflatoxin M1 in bovine milk from different agro-climatic zones of Chhattisgarh, India, using HPLC-FLD and assessment of human health risks

Concerns regarding food safety and 'One Health' are increasing globally. Aflatoxin M₁ (AFM₁), a human carcinogenic toxin, is excreted by lactating animals in their milk after consumption of feed contaminated with aflatoxin B₁. The present cross-sectional study aimed to determine the occurrence of AFM₁ in cattle and buffalo milk produced in rural and peri-urban areas under different agro-climatic conditions of Chhattisgarh, India, and assesses human health risks. Analyses of 545 milk samples by validated high-performance liquid chromatography revealed high level of AFM₁ contamination in 224 (41.1%) samples with mean concentration of 0.137 ± 0.029 μg/L. Statistically significant differences (p< 0.05) were observed in the levels and frequency of AFM₁ occurrence among different agro-climatic zones. AFM₁ was more frequently detected in milk samples from Northern hills (64%) followed by Bastar plateau (40.7%) and Chhattisgarh plain (27.3%), with mean concentration levels of 0.396 ± 0.099 μg/L, 0.081 ± 0.025 μg/L and 0.013 ± 0.002 μg/L, respectively. Species wise no significant difference was observed in the detection frequency and concentration of AFM₁ in milk from cattle and buffalo. AFM₁ contamination above maximum permissible limits established by European commission and Food Safety and Standard Authority of India was detected in 21.3% and 4.4% of samples, respectively. The estimated daily intakes for AFM₁ were found to be higher than tolerable daily intakes for both adults and children, especially of Northern hills implying a potentially high risk to consumer's health. This study provides valuable information on the contamination status of milk in one of the fastest developing state of India. It also highlights the importance and need for continuous farmers' awareness on good animal husbandry practices, routine surveillance of mycotoxins in animal feeds and food commodities to safeguard human health.

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.

Assessment of aflatoxin in milk and feed samples and impact of seasonal variations in the Punjab, Pakistan

The present study was designed to assess the incidence of aflatoxin contamination in animal feed and raw milk samples (total 240 each) collected from dairy farms during the complete year of 2015. These samples were collected through a cluster random sampling technique by dividing the province of Punjab, Pakistan into five clusters (north, south, east, west and central). Factors (environmental & physical) affecting aflatoxin contamination in milk and animal feed at farms were also studied. The AFM1 levels in raw milk & AFB1 levels in feed samples were analyzed by using the ELISA technique. Results demonstrated that overall about 53% raw milk samples from dairy farms were contaminated beyond the US MRL (0.50 µg/L) for AFM1 with than average level of 0.59 µg/L, while the 95% farm feed samples were exceeding the FDA MRL (20 µg/kg) of AFB1 with average level of 43 µg/kg. During winter season, the concentration of AFM1 was higher in all clusters with avg 0.68 µg/L, while the AFB1 contamination was highest in the spring season with avg 54 µg/kg. Market feed prices had negative correlation with AFB1 contamilevels, which were further supported by the positive correlation between quantity of feed at farms with AFM1 and AFB1 contamination. Results exhibited significantly positive impact of environmental factors on milk and feed aflatoxin contamination levels, whereas temperature showed an inverse relationship with AFM1 and AFB1 levels. The study recommends need of synergistic extension work to support dairy farms and highlight the contamination levels for regulatory bodies to introduce strategic policies for control measures.

Health risk assessment of aflatoxin M1 in infant formula milk in IR Iran

In this study, two accurate, precise, selective and sensitive methods were developed for determining aflatoxin M1 (AFM1) in infant formula milk using immunoaffinity column clean-up followed by high performance liquid chromatography (HPLC) with fluorescence detection. The validated methods were used for determination of AFM1 in 29 samples of 6 different infant formula milk brands and the risk of AFM1 in infants aged zero to 6 months old was assessed using cancer risk, Margin of Exposure (MOE) and Hazard Index (HI). Only one sample (3.4%) was contaminated with AFM1. Although the results showed that MOE values for the mean and median exposure to AFM1 was <10,000 in infants, the additional cancer risk due to mean and median exposure to AFM1 in infant <6 months were 0.00010 and 0.00012 additional cases per year per 10⁵ individuals, respectively, which indicates no health concern. In addition, HI values for the mean and median exposure to AFM1 for infants were quite below one which indicates no health concern. To the best of our knowledge, this is the first report on risk assessment of AFM1 in infant formula milk consumed by Iranian infants <6 months old, presenting a low risk for the evaluated groups.

Mycotoxin toxicity and residue in animal products: Prevalence, consumer exposure and reduction strategies - A review

Mycotoxin residues are transferred from feed to animal products, yet, less attention has been paid to it in developing countries. There is a need to find alternative alleviation material for reducing the impact of mycotoxin. This review is meant to elucidate different additives that can reduce mycotoxin residue in animal products in the world, especially in developing countries. There is evidence of relationship between mycotoxin residue in breast milk of nursing mothers and mycotoxin exposure through crop and animal product (egg and milk) intake, especially in Asia, Africa, Middle East, Latin America, and some parts of Europe. Younger livestock tends to have more toxin residues in their tissue compared to older ones. Grazing animal are also exposed to mycotoxin intake which corresponds to high level of mycotoxins in their products including meat and milk. This review shows that phytogenic, probiotic, and prebiotic additives can decrease mycotoxin residues in milk, eggs, meat liver and other tissues of livestock. Specifically, bentonites, difructose anhydride III, yeast (Trichosporon mycotoxinivorans), Bacillus spp., or their biodegradable products can reduce mycotoxin residue in animal products. In addition, Ally isothiocyanates from mustard seed were able to mitigate mycotoxins in silo-simulated system. Evidence shows that there are now low-cost, accessible, and eco-friendly additives, which could alleviate the effect of mycotoxin in feed and food. In addition, there is need for aggressive public awareness and farmers' education on the prevalence, and danger caused by mycotoxins, as well as detoxification strategies that can reduce toxin absorption into animal products.

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.

Quantification of aflatoxin M1 carry-over rate from feed to soft cheese

•

The levels of AFM₁ in milk produced in Argentina are relatively low.

•

Milk production, fiber particle size and AFB₁ level affected the carry-over rate.

•

The greatest proportion of AFM₁ in milk is detected in whey during cheese. production.

From January to December 2016, samples of milk and feeds of dairy cattle were monthly collected. The concentration of mycotoxins in all matrices was determined using the enzymatic immunoassay technique. The average concentration of aflatoxin B₁ (AFB₁), deoxynivalenol (DON) and zearalenone (ZEA) in feed was 3.01, 218.5 and 467 ug/kg, respectively. The average AFB₁ carry-over rate was 0.84% with a variation between 0.05 to 5.93%. Particle size of the feed (P = 0.030) and individual milk production (P = 0.001) affected this rate. Mini-soft cheeses were produced using milk naturally contaminated with aflatoxin M₁ (AFM₁) as raw material to study its distribution both in whey and in cheese. The average level of AFM₁ in milk was 0.014 μg/l. None of milk samples exceeded the maximum level accepted for AFB₁ by the Southern Common Market (MERCOSUR) legislation (0.5 μg/l) and only 5.5% of samples exceeded the European Union (UE) regulations (0.05 μg/l). After the cheese elaboration, the concentration of AFM₁ was determined in whey and in cheese. The greatest proportion (60%) was detected in whey while 40% AFM₁ remained in the cheese. However, the concentration of AFM₁ was higher in the cheese compared to the original milk.

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.

Evaluation of Aflatoxin M1 Effects on the Metabolomic and Cytokinomic Profiling of a Hepatoblastoma Cell Line

Hepatoblastoma incidence has been associated with different environmental factors even if no data are reported about a correlation between aflatoxin exposure and hepatoblastoma initiation. Considering that hepatoblastoma develops in infants and children and aflatoxin M1 (AFM1), the aflatoxin B1 (AFB1) hydroxylated metabolite, can be present in mothers' milk and in marketed milk products, in this study we decided to test the effects of AFM1 on a hepatoblastoma cell line (HepG2). Firstly, we evaluated the effects of AFM1 on the cell viability, apoptosis, cell cycle, and metabolomic and cytokinomic profile of HepG2 cells after treatment. AFM1 induced: (1) a decrease of HepG2 cell viability, reaching IC50 at 9 µM; (2) the blocking of the cell cycle in the G0/G1 phase; (3) the decrease of formiate levels and incremented level of some amino acids and metabolites in HepG2 cells after treatment; and (4) the increase of the concentration of three pro-inflammatory cytokines, IL-6, IL-8, and TNF-α, and the decrease of the anti-inflammatory interleukin, IL-4. Our results show that AFM1 inhibited the growth of HepG2 cells, inducing both a modulation of the lipidic, glycolytic, and amino acid metabolism and an increase of the inflammatory status of these cells.

Occurrence of Aflatoxin M1 in cow milk in El Salvador: Results from a two-year survey

Aflatoxin M₁ (AFM₁) is a metabolite of Aflatoxin B₁ (AFB₁) and is excreted through cow´s milk. AFM₁ contamination of milk is extended geographically and there might be seasons-related variations for both prevalence and contents, with higher than average values in regions with long periods of drought like El Salvador. Therefore, this project quantified AFM₁ levels in raw cow milk and AFs in cattle feedstuffs, during the transitional dry-rainy seasons of two consecutive years and it determined the variation of occurrence and contents associated to drought. Significant variations were shown from year to year in the prevalence of contamination (30% vs. 20%) and in the average levels of AFM₁ in milk (0.056 vs 0.039 μg/kg), associated with drought and increased temperature. The AFs median levels raised significantly with the drought period (from 22.5 to 10.3 μg/kg). A significant relationship was demonstrated between AFs levels and those of AFM₁, both in the year with drought and without that condition. AFM₁ positive cases and its levels in milk increase in drought and hot conditions, AFs levels in the cattle feed tend to be higher with the same, as well. Both relationship between AFs and AFM₁ levels and their association with drought were demonstrated. So that, heat and drought stress conditions can evoke raising effects on both Aflatoxins level and occurrence due to AFM₁ in milk is a carryover from AFs contaminated feedstuffs ingested by dairy cows.

Current Status of Mycotoxin Contamination of Food Commodities in Zimbabwe

Agricultural products, especially cereal grains, serve as staple foods in sub-Saharan Africa. However, climatic conditions in this region can lead to contamination of these commodities by moulds, with subsequent production of mycotoxins posing health risks to both humans and animals. There is limited documentation on the occurrence of mycotoxins in sub-Saharan African countries, leading to the exposure of their populations to a wide variety of mycotoxins through consumption of contaminated foods. This review aims at highlighting the current status of mycotoxin contamination of food products in Zimbabwe and recommended strategies of reducing this problem. Zimbabwe is one of the African countries with very little information with regards to mycotoxin contamination of its food commodities, both on the market and at household levels. Even though evidence of multitoxin occurrence in some food commodities such as maize and other staple foods exist, available published research focuses only on Aspergillus and Fusarium mycotoxins, namely aflatoxins, deoxynivalenol (DON), trichothecenes, fumonisins, and zearalenone (ZEA). Occurrence of mycotoxins in the food chain has been mainly associated with poor agricultural practices. Analysis of mycotoxins has been done mainly using chromatographic and immunological methods. Zimbabwe has adopted European standards, but the legislation is quite flexible, with testing for mycotoxin contamination in food commodities being done voluntarily or upon request. Therefore, the country needs to tighten its legislation as well as adopt stricter standards that will improve the food safety and security of the masses.

Association between Urinary Aflatoxin (AFM₁) and Dietary Intake among Adults in Hulu Langat District, Selangor, Malaysia

Aflatoxin is a food contaminant and its exposure through the diet is frequent and ubiquitous. A long-term dietary aflatoxin exposure has been linked to the development of liver cancer in populations with high prevalence of aflatoxin contamination in foods. Therefore, this study was conducted to identify the association between urinary aflatoxin M₁ (AFM₁), a biomarker of aflatoxin exposure, with the dietary intake among adults in Hulu Langat district, Selangor, Malaysia. Certain food products have higher potential for aflatoxin contamination and these were listed in a Food Frequency Questionnaire, which was given to all study participants. This allowed us to record consumption rates for each food product listed. Concomitantly, urine samples were collected, from adults in selected areas in Hulu Langat district, for the measurement of AFM₁ levels using an ELISA kit. Of the 444 urine samples collected and tested, 199 were positive for AFM₁, with 37 of them exceeding the limit of detection (LOD) of 0.64 ng/mL. Cereal products showed the highest consumption level among all food groups, with an average intake of 512.54 g per day. Chi-square analysis showed that consumption of eggs (X² = 4.77, p = 0.03) and dairy products (X² = 19.36, p < 0.01) had significant associations with urinary AFM₁ but both food groups were having a phi and Cramer’s V value that less than 0.3, which indicated that the association between these food groups’ consumption and AFM₁ level in urine was weak.