Critical comparison of analytical performances of two immunoassay methods for rapid detection of Aflatoxin M1 in milk

Aflatoxin B1 (AFB1) is a secondary metabolite produced by some Aspergillus spp. fungi affecting many crops and feed materials. Aflatoxin M1 (AFM1), the 4-hydroxylated metabolite of AFB1, is the main AFB1-related compound present in milk and it is categorized by the IARC as “group 1 human carcinogen”. Aim of this work was to evaluate and compare analytical performances of two commercial immunoassays widely F-D-00123 Application for Approval of Publications – v.6Page 4 of 3applied for the detection of AFM1 in milk, namely strip test immunoassay and enzyme linked immunosorbent assay (ELISA). Assay validation included samples at AFM1 levels of 25, 50, 75 ng/kg and blank samples (AFM1 < 0.5 ng/kg). With respect to a screening target concentration (STC) of 50 ng/kg the two assays showed cut-off values of 37.7 ng/kg and 47.5 ng/kg for strip test and ELISA respectively, false suspect rate for blanks <0.1 % (for both assays) and false negative rate, for samples containing AFM1 at levels higher than STC, of 0.4 % (for both assays). Intermediate precision (RSDip) was <32 % for the strip test and <15 % for the ELISA. Method verification through long-term intra-laboratory quality control (QC) measurements confirmed the results from the validation study. Furthermore, a satisfactory correlation of the results obtained with both immunoassays and the AOAC Official Method 2000.08 was obtained for the analysis of cow milk samples naturally contaminated with AFM1 at levels within “not detected” (< 0.5 ng/kg) to 50 ng/kg. Finally, the extension of the scope of the strip test method to goat and sheep milk was evaluated by applying the experimental design foreseen in the EU regulation.

PECORELLI Ivan;  GUARDUCCI Natascia;  VON HOLST Christoph;  BIBI Rita;  PASCALE Michelangelo;  CIASCA Biancamaria;  LOGRIECO Antonio;  LATTANZIO Veronica; 

2021-07-01

MDPI

JRC120909

2072-6651 (online),   

https://www.mdpi.com/2072-6651/12/4/270,    https://publications.jrc.ec.europa.eu/repository/handle/JRC120909,   

10.3390/toxins12040270 (online),