Pre-monsoon and monsoon surveillance of aflatoxin and fungal contamination in maize-based poultry feeds and ingredients in Tamil Nadu, India

A statewide survey was conducted in Tamil Nadu, India, to characterise seasonal variation in aflatoxin contamination in maize-based poultry feeds and ingredients. A total of 312 samples (156 each during pre-monsoon and monsoon 2023-2024) representing maize, cereal products, oilseed meals, and compound feeds were collected from mills, farms, and retail outlets. Total aflatoxins (AFB1, AFB2, AFG1 and AFG2) were quantified by HPLC-FLD, with water activity (aw) and mycobiota profiling. Monsoon samples showed higher aw in ingredients (0.637-0.686) and feeds (0.624-0.664), with increased AFB1 incidences. Several maize-intensive categories exceeded the EU maximum limit of 20 µg/kg AFB1 in feed during the monsoon, with the highest level in maize DDGS (329 µg/kg) and Layer Mash II (64.7 µg/kg). Fungal isolates were dominated by section Flavi, <i>A. flavus</i>, <i>A. parasiticus</i>, and <i>A. nomius</i>. The study highlights a monsoon-linked, maize-centric risk and underscores the need for risk-based procurement, controlled storage, and enhanced seasonal surveillance.