Natural occurrence of aflatoxin M 1 in fresh cow milk and human milk in Penang, Malaysia

Aflatoxin M1 levels in urine and breast milk of lactating mothers in Kuala Lumpur, Malaysia

Aflatoxins are carcinogens that can contaminate food and affect various body organs especially liver and kidney. When consumed, aflatoxin B1 (AFB1) is partially metabolised into aflatoxin M1 (AFM1), which is excreted in the urine. Breast milk may also contain AFM1 due to maternal dietary intake from contaminated food. This cross-sectional study aimed to determine the levels of AFM1 in both urine and breast milk among breastfeeding mothers (n = 256). The mother's demographic information was collected during recruitment. Mothers were then scheduled for an appointment to provide a morning urine sample along with five to ten mL samples of breast milk. AFM1 levels in both samples were analysed using an enzyme-linked immunosorbent assay (ELISA). Spearman's rho and Chi-square were used to determine the associations between mean levels of AFM1 in urine and breast milk. Findings show 68.0% of urine samples were contaminated with AFM1 (mean levels = 0.08 ± 0.04 ng/mL), while 14.8% of breast milk samples had AFM1 (mean levels = 5.94 ± 1.81 ng/kg). Urine AFM1 levels were not significantly associated with AFM1 levels in breast milk (p > 0.05). This study can act as a baseline for future research examining long-term aflatoxin exposure among both mothers and infants.

Prevalence and concentration of Aflatoxin M1 in human breast milk in sub-Saharan Africa: a systematic review and meta-analysis, and cancer risk assessment

This study aimed to assess the prevalence, concentration of AFM1 in human breast milk, and to determine the risk of cancer for infants in sub-Saharan Africa. A systematic literature search was performed using PubMed, CINAHL, Web of science, global health, Cochrane, and Google Scholar electronic databases. A random-effects model was used to estimate the pooled prevalence and concentration of AFM1 in breast milk. The meta-analysis of 8 articles containing 9 studies showed the pooled prevalence of AFM1 in breast milk to be 56.18% (95% CI: 29.65-82.71) and the pooled concentration to be 31.12 ng/L (95% CI: 25.97-36.25). The cancer risk assessment indicated for both male and female 1-month infants in Sierra Leone (HI > 1) is high, and all the rest of the infants are free of risk (HI < 1). The pooled prevalence and mean concentration of AFM1 in breast milk is high. Monitoring of AFB1 concentration of commonly used foods will be of high value in reducing the burden of AFM1.

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.

Insights into Aflatoxin B1 Toxicity in Cattle: An In Vitro Whole-Transcriptomic Approach

Aflatoxins, and particularly aflatoxin B1 (AFB1), are toxic mycotoxins to humans and farm animal species, resulting in acute and chronic toxicities. At present, AFB1 is still considered a global concern with negative impacts on health, the economy, and social life. In farm animals, exposure to AFB1-contaminated feed may cause several untoward effects, liver damage being one of the most devastating ones. In the present study, we assessed in vitro the transcriptional changes caused by AFB1 in a bovine fetal hepatocyte-derived cell line (BFH12). To boost the cellular response to AFB1, cells were pre-treated with the co-planar PCB 3,3′,4,4′,5-pentachlorobiphenyl (PCB126), a known aryl hydrocarbon receptor agonist. Three experimental groups were considered: cells exposed to the vehicle only, to PCB126, and to PCB126 and AFB1. A total of nine RNA-seq libraries (three replicates/group) were constructed and sequenced. The differential expression analysis showed that PCB126 induced only small transcriptional changes. On the contrary, AFB1 deeply affected the cell transcriptome, the majority of significant genes being associated with cancer, cellular damage and apoptosis, inflammation, bioactivation, and detoxification pathways. Investigating mRNA perturbations induced by AFB1 in cattle BFH12 cells will help us to better understand AFB1 toxicodynamics in this susceptible and economically important food-producing species.

Occurrence of and Factors Associated With the Presence of Aflatoxin M1 in Breast Milk of Mothers in Fethiye, Turkey

Aflatoxins comprise a group of mycotoxins that are found in the environment. Exposure to aflatoxins has been reported to cause serious health problems in humans. Since aflatoxin M₁ (AFM₁) is secreted in breast milk, the exposure of infants to this toxin is an important concern. The aim of this study was to determine the prevalence, levels of, and factors associated with the presence of AFM₁ in breast milk of mothers in Fethiye, Turkey. Breast milk samples were taken from 100 mothers who had given birth over the period of October-November 2017. The AFM₁ content of the samples was determined via enzyme-linked immunosorbent assay. The lowest limit for milk samples in the Ridascreen® AFM₁ commercial test kit is 5 ng/L. Because of this, AFM₁ levels below 5 ng/L in the breast milk samples were assessed as negative. Of the breast milk samples tested, 53 were positive. The average AFM₁ amount in the positive samples was 6.36 ng/L (ppt; range 5.10-8.31 ng/L). Mothers who were housewives, lived in damp, humid houses, or ate spices or dried fruits and vegetables had significantly greater prevalence of AFM₁ in their breast milk than those who were employed, did not report dampness or mold in the home, or did not eat spices or dried fruits and vegetables. AFM₁ in breast milk could be an important risk factor for infant health. Informing the public about food safety could reduce the amount of AFM₁ being transferred into breast milk via food channels.

Modulation of aflatoxin B1 cytotoxicity and aflatoxin M1 synthesis by natural antioxidants in a bovine mammary epithelial cell line

Aflatoxin (AF) B1, a widespread food and feed contaminant, is bioactivated by drug metabolizing enzymes (DME) to cytotoxic and carcinogenic metabolites like AFB1-epoxide and AFM1, a dairy milk contaminant. A number of natural antioxidants have been reported to afford a certain degree of protection against AFB1 (cyto)toxicity. As the mammary gland potentially participates in the generation of AFB1 metabolites, we evaluated the role of selected natural antioxidants (i.e. curcumin, quercetin and resveratrol) in the modulation of AFB1 toxicity and metabolism using a bovine mammary epithelial cell line (BME-UV1). Quercetin and, to a lesser extent, resveratrol and curcumin from Curcuma longa (all at 5 μM) significantly counteracted the AFB1-mediated impairment of cell viability (concentration range: 96-750 nM). Moreover, quercetin was able to significantly reduce the synthesis of AFM1. The quantitative PCR analysis on genes encoding for DME (phase I and II) and antioxidant enzymes showed that AFB1 caused an overall downregulation of the detoxifying systems, and mainly of GSTA1, which mediates the GSH conjugation of the AFB1-epoxide. The negative modulation of GSTA1 was efficiently reversed in the presence of quercetin, which significantly increased GSH levels as well. It is suggested that quercetin exerts its beneficial effects by depressing the bio-transformation of AFB1 and counterbalancing its pro-oxidant effects.

Aflatoxin in foodstuffs: Occurrence and recent advances in decontamination

Aflatoxins are highly toxic compounds produced as secondary metabolites by some Aspergillus species, whose occurrence have been reported predominantly in several types of foods of low moisture content, while aflatoxin biotransformation products have been reported mainly in milk and milk products. This review deals with the occurrence of aflatoxins in some of the major food products in the last 5 years including regulatory aspects, and recent advances in detoxification strategies for contaminated foods. Aflatoxin contamination in cereals including corn and peanut is still a public health problem for some populations, especially in African countries. Despite that most of physical and chemical methods for aflatoxin detoxification may affect the nutritional properties of food, or are not safe for human consumption, gamma-radiation and ozone applications have demonstrated great potential for detoxification of aflatoxins in some food matrices. Biological methods based on removal or degradation of aflatoxins by bacterial and yeast have good perspectives, although further studies are needed to clarify the detoxification mechanisms by microorganisms and determine practical aspects of the use of these methods in food products, especially their potential effects on sensory characteristics of foods.