A systematic review and meta-analysis of published research has raised concerns about milk safety in Bangladesh, reporting that 58.7% of examined milk samples contained aflatoxin M1 (AFM1), a toxic compound associated with contaminated animal feed. The findings highlight the importance of strengthening dairy feed quality controls, milk testing and food safety monitoring across the country’s expanding dairy industry.
The assessment analysed 605 milk samples across 20 datasets drawn from 12 reports published between January 2000 and January 2026. The pooled prevalence was 58.7%, with a 95% confidence interval of 51.6% to 65.5%. However, substantial variation existed across locations and surveys, with the prediction interval ranging from 32.1% to 81.1%.
More importantly, 83% of pooled samples exceeded the European Union’s maximum level of 50 nanograms per litre, while 8% exceeded the 500 nanograms per litre limit aligned with the Codex Alimentarius value in Bangladeshi standards.
Contaminated Animal Feed Emerges as a Key Dairy Industry Concern
Aflatoxin M1 enters milk when dairy animals consume feed contaminated with aflatoxin B1 (AFB1). After ingestion, the animal’s liver converts part of the compound into AFM1, which is subsequently secreted into milk. Because the toxin can persist through pasteurisation and ultra-high-temperature processing, conventional heat treatment cannot be relied upon to eliminate this contamination.
Bangladesh’s tropical monsoon climate creates favourable conditions for fungal growth during crop production, harvesting and on-farm storage. Maize, an important energy ingredient in compound animal feed, is particularly susceptible to contamination by aflatoxin-producing fungi.
The review found that published surveys reported AFB1 concentrations of 1–103 micrograms per kilogram in maize and 0–160 micrograms per kilogram in poultry feed. Other feed ingredients, including oil cakes, bran, rice straw and soybean meal, also showed contamination. Reported cattle-feed concentrations exceeded the European Union’s 5 micrograms per kilogram limit for dairy-cattle feed in the studies discussed, although many reported means remained below the general 20 micrograms per kilogram feed maximum used for comparison.
These findings underline the importance of feed sourcing, storage management and routine testing in dairy production.
Milk Contamination Varied Across Regions and Supply Chains
The analysis found differences in AFM1 prevalence across geographical areas. Chattogram recorded a pooled prevalence of 43.7%, compared with 55.3% in Dhaka and 66.8% across other divisions and national samples. Regional differences remained statistically significant after adjustment, although the researchers cautioned that the findings were exploratory rather than proof of an established geographical pattern.
The pooled prevalence estimates were 60.4% for raw milk, 59.0% for pasteurised milk and 69.5% for ultra-high-temperature milk. Differences between milk types were not statistically significant, and the ultra-high-temperature estimate was particularly uncertain because it relied on only two datasets.
The concentration data also showed substantial variation. The sample-weighted arithmetic mean was 143 nanograms per litre, while the geometric mean was 92 nanograms per litre. One Dhaka dataset reported a much higher mean of 699.1 nanograms per litre. Removing that dataset reduced the weighted mean to 93 nanograms per litre, illustrating the influence of unusually high measurements.
Potential Risks for Children and Dairy Consumers
The researchers conducted a literature-based dietary exposure assessment using milk consumption and body-weight estimates for different age groups. The central scenario estimated AFM1 exposure at 4.22 nanograms per kilogram of body weight per day for infants aged 6–12 months and 2.29 nanograms for toddlers aged 1–3 years.
Estimated margins of exposure for all age groups were below the 10,000 benchmark used to identify a potential public-health concern for genotoxic carcinogens. The authors therefore identified infants and young children as priority groups for further investigation and risk reduction.
However, these figures are screening-level estimates, not direct measurements of individual exposure or predictions of specific disease cases. The assessment also focused on milk and did not estimate exposure from other potentially contaminated foods.
Stronger Testing and Feed Management Needed
The review has important limitations. All included milk measurements relied on enzyme-linked immunosorbent assay (ELISA), without chromatographic confirmation. Many studies used convenience samples rather than representative national sampling, and the researchers did not have paired feed and milk measurements from the same herds.
The authors recommended collecting feed and milk samples from the same dairy farms across monsoon and dry seasons, confirming results with more specific analytical methods, and investigating the unusually high measurements reported in Dhaka.
For Bangladesh’s dairy industry, the findings reinforce the need for regular testing of feed ingredients and raw milk, improved feed storage, stronger quality assurance and effective monitoring throughout milk collection and processing. Coordinated action by farmers, feed manufacturers, milk processors and food safety authorities could help reduce contamination risks and protect consumer confidence.
The study, published in Veterinary Medicine and Science in 2026, provides an important evidence base for improving dairy food safety while highlighting the need for more representative national surveillance.
