Detection and Quantification of Mycotoxins in Turmeric, Cloves, And Nutmeg

Spices such as turmeric (Curcuma longa), cloves (Syzygium aromaticum), and nutmeg (Myristica fragrans) are widely used for culinary and medicinal purposes but are susceptible to fungal contamination and mycotoxin accumulation, posing potential health risks. This study evaluated the physicochemical characteristics, occurrence and co-occurrence of mycotoxins, structural confirmation, and the impact of storage conditions on toxin accumulation in selected spices. Turmeric, cloves, and nutmeg samples were obtained from Big Tree Market in Rumuolumeni, Port Harcourt, cleaned, ground into powder, and analyzed in triplicate. Moisture content was determined using the oven-drying method, water activity using a water activity meter, and pH using a calibrated digital pH meter. Mycotoxins (aflatoxins B₁, B₂, G₁, G₂ and ochratoxin A) were extracted using methanol–water and acetonitrile–water solvents and analyzed using ELISA for screening and LC-MS/MS for confirmation and quantification. Structural characterization was performed based on molecular weight, retention time, and fragmentation ions, while storage experiments were conducted at 25–45 °C and 50–90% relative humidity for 0–3 months. Results showed that turmeric had moisture content of 8.5%, water activity of 0.52 and pH 5.5, cloves recorded 10.0% moisture, aw 0.58 and pH 6.2, while nutmeg had 7.2% moisture, aw 0.48 and pH 6.5. Aflatoxin B₁ levels were 5.0 µg/kg in turmeric, 6.3 µg/kg in cloves, and 3.9 µg/kg in nutmeg, while ochratoxin A levels were 2.0 µg/kg, 2.8 µg/kg, and 1.4 µg/kg respectively. Other aflatoxins (B₂, G₁, G₂) occurred at trace levels (0.3–1.6 µg/kg). Storage experiments showed that aflatoxin B₁ in turmeric increased from 4.8 µg/kg initially to 6.5 µg/kg after 3 months at 25 °C and 50% RH and reached 8.2 µg/kg at 35 °C and 70% RH, while ochratoxin A increased to 10.5 µg/kg at 45 °C and 90% RH. Similar increases were observed in cloves and nutmeg. The study concludes that although initial mycotoxin levels were within safe limits, high temperature, humidity, and prolonged storage significantly promote toxin accumulation. Proper storage conditions and regular monitoring of spices are therefore recommended to ensure food safety and protect public health.