Evaluation of the black light test for screening aflatoxin-contaminated maize in the Brazilian food industry.
The results of the black light test for aflatoxin-contaminated maize carried out in a large food factory in the State of São Paulo was evaluated against bi-directional thin layer chromatography (TLC) analysis for 286 samples of maize. All 286 samples were accepted by the black light test (< 7 fluorescent points), however, the results from TLC analysis showed that 96 samples were contaminated and 14 showed aflatoxin B1 contamination levels higher than 20 micrograms/kg. There were 14 false negative results and no false positives and out of the 14 samples, six did not show visible fluorescent points. If the rejection criterion of one or more fluorescent points were applied, the six samples would be accepted by the black light test. But, in this case, 95 samples would be rejected and 87 results would be false positives because they did not have contamination levels over 20 micrograms/kg which is the acceptance limit of the black light test. The results indicate that the black light test, as utilized by this factory, was not able to indicate lots with possible contamination and the black light test, as recommended in the literature, would produce a high number of false positives. It is necessary to make more studies on the use of black light as a screening test for possible aflatoxin B1-contaminated maize.
Gloria
E M
EM
Universidade de São Paulo, Escola Superior de Agricultura Luiz de Queiroz, Departamento de Ciéncia e Tecnologia Agroindustrial, Piracicaba, Brazil.
Fonseca
H
H
Calori-Domingues
M A
MA
Souza
I M
IM
D000348:Aflatoxins / Q000032:analysis*; D001938:Brazil; D005453:Fluorescence; D005506:Food Contamination; D014466:Ultraviolet Rays; D003313:Zea mays / Q000737:chemistry*
D000348:Aflatoxins