Regardless of where you live or who you are, food safety is crucial for human health. Pesticide residues are commonly exposed to consumers in Nigeria through their food. What consequences, if any, such chemical pollutants cause to consumer health remain unclear given the presence of pesticide residues in food. To this end, the objective is to determine the concentration of the identified pesticide in grains commonly used by farmers, and which are available directly from the open markets in the Nigerian market. Pesticide residues were quantified through a multiresidue method using a varian 3800/4000 gas chromatograph mass spectrometer was used to analyze pesticide residues. The simultaneous determination of four classes of pesticides: carbamates, organochlorines, organophosphates, and pyrethroids by gas chromatography-mass spectrometry (GC/MS) method using sample preparation on QuEChERS-citrate, was developed and validated. The results frequently showed high inter- and intra-specific contamination, which makes sense given the target market and dietary diversity in the area. This study found that grains purchased from particular markets in southwest Nigeria contained numerous pesticide residues. The MRLs set by the EU or FAO/WHO or both were surpassed by 17 out of the total 27 pesticides reported in this work in at least one grain, despite the fact that there were no published codex MRLs for some pesticide residues in some grains.These residues were dispersed among the four classes of pesticides: carbamates, organochlorines, organophosphates, and pyrethroids. In actuality, 90% of the mainly banned organochlorine pesticides exceeded MRLs. Thus, this study revealed concentration levels of organo-chloride pesticides and organo-phosphate pesticides in grain samples drawn from selected markets in southwest Nigeria. Consumers seeking high-quality food in Nigeria should take note of these facts. Notwithstanding, the small percentage of samples with detectable residues suggests that there is a need to increase the monitoring of pesticides in grains, educate farmers, and raise their awareness of the dangers of unauthorized use of pesticides that are restricted for use in agriculture, which can harm the industry's reputation as a whole.

The authors have declared no competing interest.

This study did not receive any funding

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The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

This study entitled: Evaluation of Pesticide Residues in Grain Sold at Selected Markets of Southwest Nigeria, which was submitted for ethical approval on August 15, 2020 to the Research Ethics Committee of Kwara State University. For the development of this study, the fundamental ethical principles for research involving human beings, described and established by the Resolution 466/2012 and its complementary ones, was considered and approval was granted by the Kwara State University research ethics committee.

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