Dietary Risk Assessment of Cyromazine and Its Analogue Melamine in Evaporated and Infant Milk Samples in Nigeria

Background: The safety of milk is considered as a significant public health consideration and has been a key concern for consumers worldwide. The concentrations of cyromazine and its metabolic product, melamine, and their dietary risk assessment are investigated in this study. Methods: A total of ۱۸۲ milk samples containing ۱۵ brands were sampled between June and December ۲۰۲۲ from major and retail markets in Nigeria. After a solid-phase extraction procedure, the concentrations of the two compounds were determined using High-Performance Liquid Chromatography coupled with a Diode-Array Detector. Solid-phase extraction was utilized to extract local and imported evaporated and infant milk with CCl۳COOH and CH۳CN, followed by clean-up with NH۴OH in MeOH. The extracts were analyzed with Agilent High-Performance Liquid Chromatography, including a Zorbax Eclipse+C۱۸ column. Results: For both melamine and cyromazine, the Limits of Detection and Limits of Quantification were ۱.۲۹-۱.۴۸ and ۳.۹۴-۴.۵۰ µg/kg, respectively. The precision (Relative Standard Deviation<۱), recovery (۹۹.۵–۱۰۲.۵%), and regression (r۲=۰.۹۸۹) were all excellent. Melamine concentration ranged between ۵۷.۶±۱۸.۹ and ۹۳۰.۳±۳۷۹.۹ µg/kg among the samples, and cyromazine was ۵۷.۲±۱۲.۳ and ۶۷۰.۹±۸۷.۸ µg/kg. Brand ۲, imported from Holland, had the highest detection frequency for the two analytes. Disturbing levels of melamine were detected in Brand ۲, particularly that ۷۵ and ۹۵% of the samples had melamine above the acceptable Maximum Residue Limit.  However, the estimated daily exposure to the two additives was below the allowed daily intake values, and the Hazard Index (HI) in the different milk samples ranged from ۰.۰۲ to ۱.۲۲, with one sample having HI>۱. Conclusion: The exposure risk of melamine and cyromazine among the general population is acceptable, and smaller HI values demonstrated no significant potential risk for the Nigerian population according to the recommended guidelines. Regulatory agencies are encouraged to step up their surveillance activities to forestall the inclusion of prohibited additives in local and imported milk to protect public health. DOI: ۱۰.۱۸۵۰۲/jfqhc.۱۱.۱.۱۴۹۹۴

Keywords:

Dietary Exposure , Infant , Milk , Chromatography , High-Pressure Liquid , Nigeria