The aim of this study was to measure the standard parameters of intra-validation of the total aflatoxin low-matrix ELISA Kit (Lot No. 062218, RENEKABIO, USA) and the method was used to evaluate the contamination degree in 4 different spices [white pepper (Piper nigrum), black pepper (Piper nigrum), njansang (Ricinodendron heudelottii) and super mbongo spice (Aframomum citratum, Monodora myristica and Afrostyrax lepidophyllus)] in Cameroon market and commonly used as ingredients in Cameroonian sauces. The test was performed as a solid phase direct competitive ELISA using a horse radish peroxidase conjugate as the competing, measurable entity.
Data obtained from internal validation showed linearity in the range between 0 ?g kg-1 and 20 ?g kg-1; an accuracy marked by a recovery rate ranging from 95.09 % to 110.29 %; a coefficient of variation (CV) of repeatability of 3.14 %, a coefficient of variation (CV) of intermediate precision of 6.82 % and a coefficient of variation (CV) of reproducibility of 13.96 %. Detection and quantification limits of 0.15 ?g kg -1 and 0.50 ?g kg -1 were determined, respectively. The robustness test revealed a critical point of the method as an incubation for 30 minutes at room temperature. The application of the method to our spices revealed 100 % contamination of 2.34 ± 0.25 µg kg -1 (white pepper), 2.37 ± 0.38 µg kg -1 (black pepper), 2.58 ± 0.87 µg kg -1 (Njansang) and 6.60 ± 5.21 µg kg -1 (Super épice mbongo).
The RENEKABIO low matrix ELISA kits used for this research enables an accurate, reliable and faithful screening and quantification of total aflatoxins (B1, B2, G1, G2) in spices. This will be an asset in quality control of spices in Cameroon market.
Keywords: Spices, Total Aflatoxins, ELISA, Intra-Validation